diff --git a/routers/web/repo/issue.go b/routers/web/repo/issue.go
index bb4185f785..e1ee785ce4 100644
--- a/routers/web/repo/issue.go
+++ b/routers/web/repo/issue.go
@@ -604,7 +604,7 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		repoOwnerType = project_model.TypeOrganization
 	}
 	var err error
-	projects, err := db.Find[project_model.Project](ctx, project_model.SearchOptions{
+	repositoryProjects, err := db.Find[project_model.Project](ctx, project_model.SearchOptions{
 		ListOptions: db.ListOptionsAll,
 		RepoID:      repo.ID,
 		IsClosed:    optional.Some(false),
@@ -614,7 +614,7 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		ctx.ServerError("GetProjects", err)
 		return
 	}
-	projects2, err := db.Find[project_model.Project](ctx, project_model.SearchOptions{
+	ownerProjects, err := db.Find[project_model.Project](ctx, project_model.SearchOptions{
 		ListOptions: db.ListOptionsAll,
 		OwnerID:     repo.OwnerID,
 		IsClosed:    optional.Some(false),
@@ -625,9 +625,10 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		return
 	}
 
-	ctx.Data["OpenProjects"] = append(projects, projects2...)
+	ownerHasOpenProjects := len(ownerProjects) > 0
+	ctx.Data["OpenProjects"] = append(repositoryProjects, ownerProjects...)
 
-	projects, err = db.Find[project_model.Project](ctx, project_model.SearchOptions{
+	repositoryProjects, err = db.Find[project_model.Project](ctx, project_model.SearchOptions{
 		ListOptions: db.ListOptionsAll,
 		RepoID:      repo.ID,
 		IsClosed:    optional.Some(true),
@@ -637,7 +638,7 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		ctx.ServerError("GetProjects", err)
 		return
 	}
-	projects2, err = db.Find[project_model.Project](ctx, project_model.SearchOptions{
+	ownerProjects, err = db.Find[project_model.Project](ctx, project_model.SearchOptions{
 		ListOptions: db.ListOptionsAll,
 		OwnerID:     repo.OwnerID,
 		IsClosed:    optional.Some(true),
@@ -648,7 +649,8 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		return
 	}
 
-	ctx.Data["ClosedProjects"] = append(projects, projects2...)
+	ctx.Data["OwnerHasProjects"] = ownerHasOpenProjects || len(ownerProjects) > 0
+	ctx.Data["ClosedProjects"] = append(repositoryProjects, ownerProjects...)
 }
 
 // repoReviewerSelection items to bee shown
@@ -968,6 +970,14 @@ func NewIssue(ctx *context.Context) {
 
 	isProjectsEnabled := ctx.Repo.CanRead(unit.TypeProjects)
 	ctx.Data["IsProjectsEnabled"] = isProjectsEnabled
+
+	// Individuals always have projects unit enabled
+	isOwnerProjectsEnabled := true
+	if ctx.Repo.Owner.IsOrganization() {
+		isOwnerProjectsEnabled = ctx.Org.CanReadUnit(ctx, unit.TypeProjects)
+	}
+	ctx.Data["IsOwnerProjectsEnabled"] = isOwnerProjectsEnabled
+
 	ctx.Data["IsAttachmentEnabled"] = setting.Attachment.Enabled
 	upload.AddUploadContext(ctx, "comment")
 
@@ -983,7 +993,7 @@ func NewIssue(ctx *context.Context) {
 	}
 
 	projectID := ctx.FormInt64("project")
-	if projectID > 0 && isProjectsEnabled {
+	if projectID > 0 && (isProjectsEnabled || isOwnerProjectsEnabled) {
 		project, err := project_model.GetProjectByID(ctx, projectID)
 		if err != nil {
 			log.Error("GetProjectByID: %d: %v", projectID, err)
@@ -1276,9 +1286,9 @@ func NewIssuePost(ctx *context.Context) {
 	}
 
 	if projectID > 0 {
-		if !ctx.Repo.CanRead(unit.TypeProjects) {
+		if !ctx.Repo.CanRead(unit.TypeProjects) || (ctx.ContextUser.IsOrganization() && !ctx.Org.CanReadUnit(ctx, unit.TypeProjects)) {
 			// User must also be able to see the project.
-			ctx.Error(http.StatusBadRequest, "user hasn't permissions to read projects")
+			ctx.Error(http.StatusForbidden, "user doesn't have permissions to read projects")
 			return
 		}
 		if err := issues_model.IssueAssignOrRemoveProject(ctx, issue, ctx.Doer, projectID, 0); err != nil {
@@ -1477,7 +1487,8 @@ func ViewIssue(ctx *context.Context) {
 	}
 
 	ctx.Data["IsModerationEnabled"] = setting.Moderation.Enabled
-	ctx.Data["IsProjectsEnabled"] = ctx.Repo.CanRead(unit.TypeProjects)
+	isProjectsEnabled := ctx.Repo.CanRead(unit.TypeProjects)
+	ctx.Data["IsProjectsEnabled"] = isProjectsEnabled
 	ctx.Data["IsAttachmentEnabled"] = setting.Attachment.Enabled
 	upload.AddUploadContext(ctx, "comment")
 
@@ -1546,6 +1557,7 @@ func ViewIssue(ctx *context.Context) {
 	}
 	ctx.Data["Labels"] = labels
 
+	isOwnerProjectsEnabled := true
 	if repo.Owner.IsOrganization() {
 		orgLabels, err := issues_model.GetLabelsByOrgID(ctx, repo.Owner.ID, ctx.FormString("sort"), db.ListOptions{})
 		if err != nil {
@@ -1553,9 +1565,11 @@ func ViewIssue(ctx *context.Context) {
 			return
 		}
 		ctx.Data["OrgLabels"] = orgLabels
-
 		labels = append(labels, orgLabels...)
+
+		isOwnerProjectsEnabled = ctx.Org.CanReadUnit(ctx, unit.TypeProjects)
 	}
+	ctx.Data["IsOwnerProjectsEnabled"] = isOwnerProjectsEnabled
 
 	hasSelected := false
 	for i := range labels {
@@ -1569,7 +1583,9 @@ func ViewIssue(ctx *context.Context) {
 	// Check milestone and assignee.
 	if ctx.Repo.CanWriteIssuesOrPulls(issue.IsPull) {
 		RetrieveRepoMilestonesAndAssignees(ctx, repo)
-		retrieveProjects(ctx, repo)
+		if isProjectsEnabled || isOwnerProjectsEnabled {
+			retrieveProjects(ctx, repo)
+		}
 
 		if ctx.Written() {
 			return
diff --git a/routers/web/repo/issue_test.go b/routers/web/repo/issue_test.go
index 3644dd131f..e2c812084d 100644
--- a/routers/web/repo/issue_test.go
+++ b/routers/web/repo/issue_test.go
@@ -74,6 +74,9 @@ func TestNewIssueValidateProject(t *testing.T) {
 			contexttest.LoadUser(t, ctx, testCase.userID)
 			contexttest.LoadRepo(t, ctx, testCase.repoID)
 			contexttest.LoadGitRepo(t, ctx)
+			if ctx.Repo.Owner.IsOrganization() {
+				contexttest.LoadOrganization(t, ctx, ctx.Repo.Owner.ID)
+			}
 
 			NewIssue(ctx)
 
diff --git a/routers/web/repo/projects.go b/routers/web/repo/projects.go
index 98e4c35fa2..f007dfa7ba 100644
--- a/routers/web/repo/projects.go
+++ b/routers/web/repo/projects.go
@@ -400,7 +400,7 @@ func UpdateIssueProject(ctx *context.Context) {
 		return
 	}
 	if _, err := issues.LoadRepositories(ctx); err != nil {
-		ctx.ServerError("LoadProjects", err)
+		ctx.ServerError("LoadRepositories", err)
 		return
 	}
 
diff --git a/routers/web/web.go b/routers/web/web.go
index 5839e7d30e..c77c8629b9 100644
--- a/routers/web/web.go
+++ b/routers/web/web.go
@@ -906,6 +906,29 @@ func registerRoutes(m *web.Route) {
 		}
 	}
 
+	reqRepoOrOwnerProjectReader := func(ctx *context.Context) {
+		unitType := unit.TypeProjects
+		if ctx.ContextUser == nil || ctx.Doer == nil {
+			ctx.NotFound(unitType.String(), nil)
+			return
+		}
+
+		switch {
+		case ctx.ContextUser.IsIndividual():
+			if ctx.Doer.ID == ctx.ContextUser.ID || ctx.Doer.IsAdmin {
+				return
+			}
+		case ctx.ContextUser.IsOrganization():
+			if ctx.Org.Organization.UnitPermission(ctx, ctx.Doer, unitType) >= perm.AccessModeRead {
+				return
+			}
+		default:
+			ctx.NotFound(unitType.String(), nil)
+			return
+		}
+		reqRepoProjectsReader(ctx)
+	}
+
 	individualPermsChecker := func(ctx *context.Context) {
 		// org permissions have been checked in context.OrgAssignment(), but individual permissions haven't been checked.
 		if ctx.ContextUser.IsIndividual() {
@@ -1255,7 +1278,7 @@ func registerRoutes(m *web.Route) {
 		}
 		m.Group("/issues", func() {
 			m.Group("/new", func() {
-				m.Combo("").Get(context.RepoRef(), repo.NewIssue).
+				m.Combo("", context.EnsureOrg()).Get(context.RepoRef(), repo.NewIssue).
 					Post(web.Bind(forms.CreateIssueForm{}), repo.NewIssuePost)
 				m.Get("/choose", context.RepoRef(), repo.NewIssueChooseTemplate)
 			})
@@ -1301,7 +1324,7 @@ func registerRoutes(m *web.Route) {
 
 			m.Post("/labels", reqRepoIssuesOrPullsWriter, repo.UpdateIssueLabel)
 			m.Post("/milestone", reqRepoIssuesOrPullsWriter, repo.UpdateIssueMilestone)
-			m.Post("/projects", reqRepoIssuesOrPullsWriter, reqRepoProjectsReader, repo.UpdateIssueProject)
+			m.Post("/projects", reqRepoIssuesOrPullsWriter, context.EnsureOrg(), reqRepoOrOwnerProjectReader, repo.UpdateIssueProject)
 			m.Post("/assignee", reqRepoIssuesOrPullsWriter, repo.UpdateIssueAssignee)
 			m.Post("/request_review", reqRepoIssuesOrPullsReader, repo.UpdatePullReviewRequest)
 			m.Post("/dismiss_review", reqRepoAdmin, web.Bind(forms.DismissReviewForm{}), repo.DismissReview)
@@ -1427,7 +1450,7 @@ func registerRoutes(m *web.Route) {
 		m.Group("", func() {
 			m.Get("/issues/posters", repo.IssuePosters) // it can't use {type:issues|pulls} because other routes like "/pulls/{index}" has higher priority
 			m.Get("/{type:^(issues|pulls)$}", repo.Issues)
-			m.Get("/{type:^(issues|pulls)$}/{index}", repo.ViewIssue)
+			m.Get("/{type:^(issues|pulls)$}/{index}", context.EnsureOrg(), repo.ViewIssue)
 			m.Group("/{type:^(issues|pulls)$}/{index}/content-history", func() {
 				m.Get("/overview", repo.GetContentHistoryOverview)
 				m.Get("/list", repo.GetContentHistoryList)
@@ -1600,7 +1623,7 @@ func registerRoutes(m *web.Route) {
 
 		m.Get("/pulls/posters", repo.PullPosters)
 		m.Group("/pulls/{index}", func() {
-			m.Get("", repo.SetWhitespaceBehavior, repo.GetPullDiffStats, repo.ViewIssue)
+			m.Get("", repo.SetWhitespaceBehavior, repo.GetPullDiffStats, context.EnsureOrg(), repo.ViewIssue)
 			m.Get(".diff", repo.DownloadPullDiff)
 			m.Get(".patch", repo.DownloadPullPatch)
 			m.Group("/commits", func() {
diff --git a/services/context/org.go b/services/context/org.go
index c7d06b9bcc..adc6e33494 100644
--- a/services/context/org.go
+++ b/services/context/org.go
@@ -64,6 +64,32 @@ func GetOrganizationByParams(ctx *Context) {
 	}
 }
 
+func ensureIsOrg(ctx *Context) bool {
+	switch {
+	// Getting Organization from params
+	case ctx.ContextUser == nil:
+		if ctx.Org.Organization == nil {
+			GetOrganizationByParams(ctx)
+		}
+		return !ctx.Written()
+	// Getting Organization from ContextUser
+	case ctx.ContextUser.IsOrganization():
+		if ctx.Org == nil {
+			ctx.Org = &Organization{}
+		}
+		ctx.Org.Organization = (*organization.Organization)(ctx.ContextUser)
+		return true
+	}
+	// ContextUser is an individual User
+	return false
+}
+
+func EnsureOrg() func(*Context) {
+	return func(ctx *Context) {
+		ensureIsOrg(ctx)
+	}
+}
+
 // HandleOrgAssignment handles organization assignment
 func HandleOrgAssignment(ctx *Context, args ...bool) {
 	var (
@@ -87,24 +113,9 @@ func HandleOrgAssignment(ctx *Context, args ...bool) {
 
 	var err error
 
-	if ctx.ContextUser == nil {
-		// if Organization is not defined, get it from params
-		if ctx.Org.Organization == nil {
-			GetOrganizationByParams(ctx)
-			if ctx.Written() {
-				return
-			}
-		}
-	} else if ctx.ContextUser.IsOrganization() {
-		if ctx.Org == nil {
-			ctx.Org = &Organization{}
-		}
-		ctx.Org.Organization = (*organization.Organization)(ctx.ContextUser)
-	} else {
-		// ContextUser is an individual User
+	if !ensureIsOrg(ctx) {
 		return
 	}
-
 	org := ctx.Org.Organization
 
 	// Handle Visibility
diff --git a/templates/repo/issue/new_form.tmpl b/templates/repo/issue/new_form.tmpl
index 10a5978d52..5f5820fb07 100644
--- a/templates/repo/issue/new_form.tmpl
+++ b/templates/repo/issue/new_form.tmpl
@@ -78,7 +78,7 @@
 			</div>
 		</div>
 
-		{{if .IsProjectsEnabled}}
+		{{if or .IsProjectsEnabled (and .OwnerHasProjects .IsOwnerProjectsEnabled)}}
 		<div class="divider"></div>
 
 		<input id="project_id" name="project_id" type="hidden" value="{{.project_id}}">
diff --git a/templates/repo/issue/view_content/sidebar.tmpl b/templates/repo/issue/view_content/sidebar.tmpl
index 72e214c5aa..9d8db413fa 100644
--- a/templates/repo/issue/view_content/sidebar.tmpl
+++ b/templates/repo/issue/view_content/sidebar.tmpl
@@ -14,8 +14,10 @@
 	{{template "repo/issue/view_content/sidebar/milestones" .}}
 	<div class="divider"></div>
 
-	{{template "repo/issue/view_content/sidebar/projects" .}}
-	<div class="divider"></div>
+	{{if or .IsProjectsEnabled (and .OwnerHasProjects .IsOwnerProjectsEnabled)}}
+		{{template "repo/issue/view_content/sidebar/projects" .}}
+		<div class="divider"></div>
+	{{end}}
 
 	{{template "repo/issue/view_content/sidebar/assignees" dict "isExistingIssue" true "." .}}
 	<div class="divider"></div>
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/HEAD b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/HEAD
new file mode 100644
index 0000000000..cb089cd89a
--- /dev/null
+++ b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/HEAD
@@ -0,0 +1 @@
+ref: refs/heads/master
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/config b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/config
new file mode 100644
index 0000000000..e6da231579
--- /dev/null
+++ b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/config
@@ -0,0 +1,6 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = true
+	ignorecase = true
+	precomposeunicode = true
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/description b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/description
new file mode 100644
index 0000000000..498b267a8c
--- /dev/null
+++ b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/description
@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/info/exclude b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/info/exclude
new file mode 100644
index 0000000000..a5196d1be8
--- /dev/null
+++ b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/info/exclude
@@ -0,0 +1,6 @@
+# git ls-files --others --exclude-from=.git/info/exclude
+# Lines that start with '#' are comments.
+# For a project mostly in C, the following would be a good set of
+# exclude patterns (uncomment them if you want to use them):
+# *.[oa]
+# *~
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/20/ade30d25e0ecaeec84e7f542a8456900858240 b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/20/ade30d25e0ecaeec84e7f542a8456900858240
new file mode 100644
index 0000000000..9f3ffe5f27
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/20/ade30d25e0ecaeec84e7f542a8456900858240 differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/27/74debeea6dc742cc4971a92db0e08b95b60588 b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/27/74debeea6dc742cc4971a92db0e08b95b60588
new file mode 100644
index 0000000000..5d9226f7a1
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/27/74debeea6dc742cc4971a92db0e08b95b60588 differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/2a/47ca4b614a9f5a43abbd5ad851a54a616ffee6 b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/2a/47ca4b614a9f5a43abbd5ad851a54a616ffee6
new file mode 100644
index 0000000000..ca60d2314f
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/2a/47ca4b614a9f5a43abbd5ad851a54a616ffee6 differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/2f/9b22fd3159a43b7b4e5dd806fcd544edf8716f b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/2f/9b22fd3159a43b7b4e5dd806fcd544edf8716f
new file mode 100644
index 0000000000..e98d752dad
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/2f/9b22fd3159a43b7b4e5dd806fcd544edf8716f differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/d2/2b4d4daa5be07329fcef6ed458f00cf3392da0 b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/d2/2b4d4daa5be07329fcef6ed458f00cf3392da0
new file mode 100644
index 0000000000..e319f8ce34
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/d2/2b4d4daa5be07329fcef6ed458f00cf3392da0 differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/d5/6a3073c1dbb7b15963110a049d50cdb5db99fc b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/d5/6a3073c1dbb7b15963110a049d50cdb5db99fc
new file mode 100644
index 0000000000..eff3c9833e
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/d5/6a3073c1dbb7b15963110a049d50cdb5db99fc differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/ec/f0db3c1ec806522de4b491fb9a3c7457398c61 b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/ec/f0db3c1ec806522de4b491fb9a3c7457398c61
new file mode 100644
index 0000000000..ed431f70d3
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/ec/f0db3c1ec806522de4b491fb9a3c7457398c61 differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/ee/16d127df463aa491e08958120f2108b02468df b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/ee/16d127df463aa491e08958120f2108b02468df
new file mode 100644
index 0000000000..e177f69e37
Binary files /dev/null and b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/objects/ee/16d127df463aa491e08958120f2108b02468df differ
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/refs/heads/master b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/refs/heads/master
new file mode 100644
index 0000000000..ccee722d52
--- /dev/null
+++ b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/refs/heads/master
@@ -0,0 +1 @@
+2a47ca4b614a9f5a43abbd5ad851a54a616ffee6
diff --git a/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/refs/heads/test_branch b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/refs/heads/test_branch
new file mode 100644
index 0000000000..dfe0c6a128
--- /dev/null
+++ b/tests/gitea-repositories-meta/test_assign_project_org/test_assign_project_repo.git/refs/heads/test_branch
@@ -0,0 +1 @@
+d22b4d4daa5be07329fcef6ed458f00cf3392da0
diff --git a/tests/integration/fixtures/TestAssignProject/access.yml b/tests/integration/fixtures/TestAssignProject/access.yml
new file mode 100644
index 0000000000..9dec50f0ac
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/access.yml
@@ -0,0 +1,5 @@
+-
+  id: 1001
+  user_id: 5
+  repo_id: 1001
+  mode: 2
diff --git a/tests/integration/fixtures/TestAssignProject/collaboration.yml b/tests/integration/fixtures/TestAssignProject/collaboration.yml
new file mode 100644
index 0000000000..a26149d60e
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/collaboration.yml
@@ -0,0 +1,5 @@
+-
+  id: 1001
+  repo_id: 1001
+  user_id: 5
+  mode: 2
diff --git a/tests/integration/fixtures/TestAssignProject/project.yml b/tests/integration/fixtures/TestAssignProject/project.yml
new file mode 100644
index 0000000000..20b75ddb69
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/project.yml
@@ -0,0 +1,51 @@
+# team 1001 projects
+-
+  id: 1001
+  title: project1001
+  owner_id: 3
+  repo_id: 0
+  is_closed: false
+  board_type: 0
+  type: 3
+  creator_id: 5
+  created_unix: 1688973030
+  updated_unix: 1688973030
+
+# team 1002 projects
+-
+  id: 1002
+  title: project1002
+  owner_id: 0
+  repo_id: 1001
+  is_closed: false
+  board_type: 0
+  type: 2
+  creator_id: 5
+  created_unix: 1688973030
+  updated_unix: 1688973030
+
+# user 5 project
+-
+  id: 1003
+  title: project1003
+  owner_id: 5
+  repo_id: 0
+  is_closed: false
+  board_type: 0
+  type: 1
+  creator_id: 5
+  created_unix: 1688973030
+  updated_unix: 1688973030
+
+# org 1001 disabled project
+-
+  id: 1004
+  title: project1004
+  owner_id: 1001
+  repo_id: 0
+  is_closed: false
+  board_type: 0
+  type: 3
+  creator_id: 5
+  created_unix: 1688973030
+  updated_unix: 1688973030
diff --git a/tests/integration/fixtures/TestAssignProject/repo_unit.yml b/tests/integration/fixtures/TestAssignProject/repo_unit.yml
new file mode 100644
index 0000000000..d3fad496aa
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/repo_unit.yml
@@ -0,0 +1,35 @@
+-
+  id: 1001
+  repo_id: 3
+  type: 8
+  created_unix: 946684810
+
+-
+  id: 1002
+  repo_id: 3
+  type: 2
+  created_unix: 946684810
+
+-
+  id: 1003
+  repo_id: 3
+  type: 3
+  created_unix: 946684810
+
+-
+  id: 1004
+  repo_id: 1001
+  type: 8
+  created_unix: 946684810
+
+-
+  id: 1005
+  repo_id: 1001
+  type: 2
+  created_unix: 946684810
+
+-
+  id: 1006
+  repo_id: 1001
+  type: 3
+  created_unix: 946684810
diff --git a/tests/integration/fixtures/TestAssignProject/repository.yml b/tests/integration/fixtures/TestAssignProject/repository.yml
new file mode 100644
index 0000000000..3a2d6d637a
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/repository.yml
@@ -0,0 +1,30 @@
+-
+  id: 1001
+  owner_id: 1001
+  owner_name: test_assign_project_org
+  lower_name: test_assign_project_repo
+  name: test_assign_project_repo
+  default_branch: master
+  num_watches: 4
+  num_stars: 0
+  num_forks: 0
+  num_milestones: 3
+  num_closed_milestones: 1
+  num_projects: 1
+  num_closed_projects: 0
+  is_private: false
+  is_empty: false
+  is_archived: false
+  is_mirror: false
+  status: 0
+  is_fork: false
+  fork_id: 0
+  is_template: false
+  template_id: 0
+  size: 7597
+  is_fsck_enabled: true
+  close_issues_via_commit_in_any_branch: false
+  created_unix: 1731254961
+  updated_unix: 1731254961
+  topics: '[]'
+
diff --git a/tests/integration/fixtures/TestAssignProject/team.yml b/tests/integration/fixtures/TestAssignProject/team.yml
new file mode 100644
index 0000000000..6f295a3c65
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/team.yml
@@ -0,0 +1,32 @@
+-
+  id: 1001
+  org_id: 3
+  lower_name: writers
+  name: Writers
+  authorize: 2 # writer
+  num_repos: 3
+  num_members: 1
+  includes_all_repositories: false
+  can_create_org_repo: true
+
+-
+  id: 1002
+  org_id: 1001
+  lower_name: writers
+  name: Writers
+  authorize: 2 # writer
+  num_repos: 1
+  num_members: 1
+  includes_all_repositories: false
+  can_create_org_repo: true
+
+-
+  id: 1003
+  org_id: 1001
+  lower_name: owners
+  name: Owners
+  authorize: 4
+  num_repos: 0
+  num_members: 1
+  includes_all_repositories: false
+  can_create_org_repo: true
diff --git a/tests/integration/fixtures/TestAssignProject/team_repo.yml b/tests/integration/fixtures/TestAssignProject/team_repo.yml
new file mode 100644
index 0000000000..9b34a817d9
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/team_repo.yml
@@ -0,0 +1,11 @@
+-
+  id: 1001
+  org_id: 3
+  team_id: 1001
+  repo_id: 3
+
+-
+  id: 1002
+  org_id: 1001
+  team_id: 1002
+  repo_id: 1001
diff --git a/tests/integration/fixtures/TestAssignProject/team_unit.yml b/tests/integration/fixtures/TestAssignProject/team_unit.yml
new file mode 100644
index 0000000000..d156983090
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/team_unit.yml
@@ -0,0 +1,35 @@
+-
+  id: 1001
+  team_id: 1001
+  type: 8
+  access_mode: 2
+
+-
+  id: 1002
+  team_id: 1002
+  type: 8
+  access_mode: 1
+
+-
+  id: 1003
+  team_id: 1001
+  type: 2
+  access_mode: 2
+
+-
+  id: 1004
+  team_id: 1001
+  type: 3
+  access_mode: 2
+
+-
+  id: 1005
+  team_id: 1002
+  type: 2
+  access_mode: 2
+
+-
+  id: 1006
+  team_id: 1002
+  type: 3
+  access_mode: 2
diff --git a/tests/integration/fixtures/TestAssignProject/team_user.yml b/tests/integration/fixtures/TestAssignProject/team_user.yml
new file mode 100644
index 0000000000..8061f1b9d8
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/team_user.yml
@@ -0,0 +1,11 @@
+-
+  id: 1001
+  org_id: 3
+  team_id: 1001
+  uid: 5
+
+-
+  id: 1002
+  org_id: 23
+  team_id: 1002
+  uid: 5
diff --git a/tests/integration/fixtures/TestAssignProject/user.yml b/tests/integration/fixtures/TestAssignProject/user.yml
new file mode 100644
index 0000000000..8ad7bd0e67
--- /dev/null
+++ b/tests/integration/fixtures/TestAssignProject/user.yml
@@ -0,0 +1,37 @@
+-
+  id: 1001
+  lower_name: test_assign_project_org
+  name: test_assign_project_org
+  full_name: ' <<<< >> >> > >> > >>> >> '
+  email: org1001@example.com
+  keep_email_private: false
+  email_notifications_preference: onmention
+  passwd: ZogKvWdyEx:password
+  passwd_hash_algo: dummy
+  must_change_password: false
+  login_source: 0
+  login_name: test_assign_project_org
+  type: 1
+  salt: ZogKvWdyEx
+  max_repo_creation: 1000
+  is_active: false
+  is_admin: false
+  is_restricted: false
+  allow_git_hook: false
+  allow_import_local: false
+  allow_create_organization: true
+  prohibit_login: false
+  avatar: ""
+  avatar_email: org1001@example.com
+  use_custom_avatar: true
+  num_followers: 0
+  num_following: 0
+  num_stars: 0
+  num_repos: 1
+  num_teams: 1
+  num_members: 1
+  visibility: 0
+  repo_admin_change_team_access: false
+  theme: ""
+  keep_activity_private: false
+  created_unix: 1672578020
diff --git a/tests/integration/issue_test.go b/tests/integration/issue_test.go
index d764870bab..c0ecf6b3bc 100644
--- a/tests/integration/issue_test.go
+++ b/tests/integration/issue_test.go
@@ -19,6 +19,7 @@ import (
 	auth_model "forgejo.org/models/auth"
 	"forgejo.org/models/db"
 	issues_model "forgejo.org/models/issues"
+	org_model "forgejo.org/models/organization"
 	project_model "forgejo.org/models/project"
 	repo_model "forgejo.org/models/repo"
 	unit_model "forgejo.org/models/unit"
@@ -31,6 +32,7 @@ import (
 	api "forgejo.org/modules/structs"
 	"forgejo.org/modules/test"
 	"forgejo.org/modules/translation"
+	repo_service "forgejo.org/services/repository"
 	files_service "forgejo.org/services/repository/files"
 	user_service "forgejo.org/services/user"
 	"forgejo.org/tests"
@@ -1661,3 +1663,113 @@ func TestIssueUrlHandling(t *testing.T) {
 		MakeRequest(t, req, http.StatusNotFound)
 	})
 }
+
+func TestIssueProjectSidebarMissing(t *testing.T) {
+	const (
+		repoID = 4
+		userID = 5
+	)
+	defer unittest.OverrideFixtures("tests/integration/fixtures/TestAssignProject/")()
+	defer tests.PrepareTestEnv(t)()
+
+	ctx := t.Context()
+
+	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: userID})
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: repoID})
+	session := loginUser(t, user.Name)
+
+	issueURL := testNewIssue(t, session, user.Name, repo.Name, "Hello", "World")
+	t.Run("Sidebar showing - user project available", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		req := NewRequest(t, "GET", issueURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+		htmlDoc.AssertElement(t, ".select-project.dropdown", true)
+	})
+
+	// Enable repository's project unit
+	projectUnit := repo_model.RepoUnit{
+		RepoID: repo.ID,
+		Type:   unit_model.TypeProjects,
+	}
+	require.NoError(t, repo_service.UpdateRepositoryUnits(db.DefaultContext, repo, []repo_model.RepoUnit{projectUnit}, nil))
+
+	t.Run("Sidebar showing - repository project unit on", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		req := NewRequest(t, "GET", issueURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+		htmlDoc.AssertElement(t, ".select-project.dropdown", true)
+	})
+
+	project_model.DeleteProjectByID(ctx, 1003)
+	// Disable repository's project unit
+	require.NoError(t, repo_service.UpdateRepositoryUnits(db.DefaultContext, repo, nil, []unit_model.Type{unit_model.TypeProjects}))
+	t.Run("Sidebar missing", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		req := NewRequest(t, "GET", issueURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+		htmlDoc.AssertElement(t, ".select-project.dropdown", false)
+	})
+
+	// Team with project available
+	team := unittest.AssertExistsAndLoadBean(t, &org_model.Team{ID: 1001})
+	require.NoError(t, team.LoadMembers(ctx))
+	require.NoError(t, team.LoadRepositories(ctx))
+
+	user = team.Members[0]
+	repo = team.Repos[0]
+	org := team.GetOrg(ctx)
+	session = loginUser(t, user.Name)
+
+	issueURL = testNewIssue(t, session, org.Name, repo.Name, "Hello", "World")
+	t.Run("Sidebar showing - org on & repo on", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		req := NewRequest(t, "GET", issueURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+		htmlDoc.AssertElement(t, ".select-project.dropdown", true)
+	})
+
+	// Disable repository project unit
+	require.NoError(t, repo_service.UpdateRepositoryUnits(ctx, repo, nil, []unit_model.Type{unit_model.TypeProjects}))
+	t.Run("Sidebar showing - org on & repo off", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		req := NewRequest(t, "GET", issueURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+		htmlDoc.AssertElement(t, ".select-project.dropdown", true)
+	})
+
+	// Team with project disabled
+	team = unittest.AssertExistsAndLoadBean(t, &org_model.Team{ID: 1002})
+	require.NoError(t, team.LoadMembers(ctx))
+	require.NoError(t, team.LoadRepositories(ctx))
+
+	user = team.Members[0]
+	repo = team.Repos[0]
+	org = team.GetOrg(ctx)
+	session = loginUser(t, user.Name)
+
+	require.NoError(t, project_model.DeleteProjectByID(db.DefaultContext, 1004))
+
+	issueURL = testNewIssue(t, session, org.Name, repo.Name, "Hello", "World")
+	t.Run("Sidebar showing - org off & repo on", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		req := NewRequest(t, "GET", issueURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+		htmlDoc.AssertElement(t, ".select-project.dropdown", true)
+	})
+
+	// Disable repository project unit
+	require.NoError(t, repo_service.UpdateRepositoryUnits(ctx, repo, nil, []unit_model.Type{unit_model.TypeProjects}))
+	t.Run("Sidebar missing - org off & repo off", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		req := NewRequest(t, "GET", issueURL)
+		resp := session.MakeRequest(t, req, http.StatusOK)
+		htmlDoc := NewHTMLParser(t, resp.Body)
+		htmlDoc.AssertElement(t, ".select-project.dropdown", false)
+	})
+}
diff --git a/tests/integration/project_test.go b/tests/integration/project_test.go
index 629793602b..7583075b5f 100644
--- a/tests/integration/project_test.go
+++ b/tests/integration/project_test.go
@@ -7,12 +7,20 @@ package integration
 import (
 	"fmt"
 	"net/http"
+	"path"
+	"strconv"
+	"strings"
 	"testing"
 
 	"forgejo.org/models/db"
+	issues_model "forgejo.org/models/issues"
+	org_model "forgejo.org/models/organization"
 	project_model "forgejo.org/models/project"
 	repo_model "forgejo.org/models/repo"
+	unit_model "forgejo.org/models/unit"
 	"forgejo.org/models/unittest"
+	user_model "forgejo.org/models/user"
+	repo_service "forgejo.org/services/repository"
 	"forgejo.org/tests"
 
 	"github.com/stretchr/testify/assert"
@@ -160,3 +168,117 @@ func TestChangeStatusProject(t *testing.T) {
 		})
 	})
 }
+
+func TestAssignProject(t *testing.T) {
+	defer unittest.OverrideFixtures("tests/integration/fixtures/TestAssignProject/")()
+	defer tests.PrepareTestEnv(t)()
+
+	ctx := t.Context()
+
+	newTestIssue := func(t *testing.T, session *TestSession, owner *user_model.User, repo *repo_model.Repository) (*issues_model.Issue, string, string) {
+		t.Helper()
+
+		issueURL := testNewIssue(t, session, owner.Name, repo.Name, "Hello", "World")
+		indexStr := issueURL[strings.LastIndexByte(issueURL, '/')+1:]
+		index, err := strconv.Atoi(indexStr)
+		require.NoError(t, err, "Invalid issue href: %s", issueURL)
+
+		issue := &issues_model.Issue{RepoID: repo.ID, Index: int64(index)}
+		unittest.AssertExistsAndLoadBean(t, issue)
+
+		issueID := strconv.FormatInt(issue.ID, 10)
+		return issue, indexStr, issueID
+	}
+
+	updateIssueProject := func(t *testing.T, session *TestSession, projectID, issueID, owner, repo string, expectedStatus int) {
+		t.Helper()
+
+		req := NewRequestWithValues(t, "POST", path.Join(owner, repo, "issues", "projects"), map[string]string{
+			"issue_ids": issueID,
+			"id":        projectID,
+		})
+		session.MakeRequest(t, req, expectedStatus)
+	}
+
+	// User
+	t.Run("UserProjectOn+RepoProjectOff", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 4})
+		user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+
+		session := loginUser(tt, user.Name)
+		issue, _, issueID := newTestIssue(tt, session, user, repo)
+
+		updateIssueProject(tt, session, "1003", issueID, user.Name, repo.Name, http.StatusOK)
+		require.NoError(tt, issue.LoadProject(db.DefaultContext))
+		require.NotNil(tt, issue.Project)
+		require.Equal(tt, int64(1003), issue.Project.ID)
+	})
+
+	// Team 1001 - enabled project unit
+	team := unittest.AssertExistsAndLoadBean(t, &org_model.Team{ID: 1001})
+	require.NoError(t, team.LoadMembers(ctx))
+	require.NoError(t, team.LoadRepositories(ctx))
+
+	user := team.Members[0]
+	repo := team.Repos[0]
+	org := team.GetOrg(ctx)
+
+	session := loginUser(t, user.Name)
+
+	t.Run("OrgProjectOn+RepoProjectOn", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		issue, _, issueID := newTestIssue(tt, session, org.AsUser(), repo)
+
+		updateIssueProject(tt, session, "1001", issueID, org.Name, repo.Name, http.StatusOK)
+
+		require.NoError(tt, issue.LoadProject(db.DefaultContext))
+		require.NotNil(tt, issue.Project)
+		require.Equal(tt, int64(1001), issue.Project.ID)
+	})
+
+	// Disable repository project unit
+	require.NoError(t, repo_service.UpdateRepositoryUnits(ctx, repo, nil, []unit_model.Type{unit_model.TypeProjects}))
+	t.Run("OrgProjectOn+RepoProjectOff", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		issue, _, issueID := newTestIssue(tt, session, org.AsUser(), repo)
+
+		updateIssueProject(tt, session, "1001", issueID, org.Name, repo.Name, http.StatusOK)
+		require.NoError(tt, issue.LoadProject(db.DefaultContext))
+		require.NotNil(tt, issue.Project)
+		require.Equal(tt, int64(1001), issue.Project.ID)
+	})
+
+	// Team 1002 - disabled project unit
+	team = unittest.AssertExistsAndLoadBean(t, &org_model.Team{ID: 1002})
+	require.NoError(t, team.LoadMembers(ctx))
+	require.NoError(t, team.LoadRepositories(ctx))
+
+	user = team.Members[0]
+	repo = team.Repos[0]
+	org = team.GetOrg(ctx)
+
+	session = loginUser(t, user.Name)
+
+	t.Run("OrgProjectOff+RepoProjectOn", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		issue, _, issueID := newTestIssue(tt, session, org.AsUser(), repo)
+
+		updateIssueProject(tt, session, "1002", issueID, org.Name, repo.Name, http.StatusOK)
+		require.NoError(tt, issue.LoadProject(db.DefaultContext))
+		require.NotNil(tt, issue.Project)
+		require.Equal(tt, int64(1002), issue.Project.ID)
+	})
+
+	// Disable repository project unit
+	require.NoError(t, repo_service.UpdateRepositoryUnits(ctx, repo, nil, []unit_model.Type{unit_model.TypeProjects}))
+	t.Run("OrgProjectOff+RepoProjectOff", func(tt *testing.T) {
+		defer tests.PrintCurrentTest(tt)()
+		issue, _, issueID := newTestIssue(tt, session, org.AsUser(), repo)
+
+		updateIssueProject(tt, session, "1002", issueID, org.Name, repo.Name, http.StatusOK)
+		require.NoError(tt, issue.LoadProject(db.DefaultContext))
+		require.NotNil(tt, issue.Project)
+		require.Equal(tt, int64(1002), issue.Project.ID)
+	})
+}