diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index 03d42c2140..7fee0c2a99 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -492,6 +492,7 @@ migrate.lfs_mirror_unsupported = Mirroring LFS objects is not supported - use 'g
 
 mirror_from = mirror of
 forked_from = forked from
+fork_from_self = You cannot fork a repository you already own!
 copy_link = Copy
 copy_link_success = Copied!
 copy_link_error = Press ⌘-C or Ctrl-C to copy
diff --git a/routers/repo/pull.go b/routers/repo/pull.go
index b17c26e779..ad4a01ec94 100644
--- a/routers/repo/pull.go
+++ b/routers/repo/pull.go
@@ -111,6 +111,12 @@ func ForkPost(ctx *context.Context, form auth.CreateRepoForm) {
 		return
 	}
 
+	repo, has := models.HasForkedRepo(ctxUser.ID, forkRepo.ID)
+	if has {
+		ctx.Redirect(setting.AppSubURL + "/" + ctxUser.Name + "/" + repo.Name)
+		return
+	}
+
 	// Check ownership of organization.
 	if ctxUser.IsOrganization() {
 		if !ctxUser.IsOwnedBy(ctx.User.ID) {
diff --git a/templates/repo/header.tmpl b/templates/repo/header.tmpl
index ed90491309..db636eb9bd 100644
--- a/templates/repo/header.tmpl
+++ b/templates/repo/header.tmpl
@@ -32,7 +32,7 @@
 						</div>
 						{{if .CanBeForked}}
 							<div class="ui compact labeled button" tabindex="0">
-								<a class="ui compact button" href="{{AppSubUrl}}/repo/fork/{{.ID}}">
+								<a class="ui compact button {{if eq .OwnerID $.SignedUserID}}poping up{{end}}" {{if not (eq .OwnerID $.SignedUserID)}}href="{{AppSubUrl}}/repo/fork/{{.ID}}"{{else}} data-content="{{$.i18n.Tr "repo.fork_from_self"}}" data-position="top center" data-variation="tiny"{{end}}>
 									<i class="octicon octicon-repo-forked"></i>{{$.i18n.Tr "repo.fork"}}
 								</a>
 								<a class="ui basic label" href="{{.Link}}/forks">