diff --git a/services/automerge/automerge_test.go b/services/automerge/automerge_test.go
index 4ad5b70cce..38ed4dcd9f 100644
--- a/services/automerge/automerge_test.go
+++ b/services/automerge/automerge_test.go
@@ -15,6 +15,7 @@ import (
 	"forgejo.org/models/unittest"
 	user_model "forgejo.org/models/user"
 	"forgejo.org/modules/util"
+
 	"github.com/stretchr/testify/require"
 )
 
diff --git a/tests/integration/pull_auto_merge_test.go b/tests/integration/pull_auto_merge_test.go
new file mode 100644
index 0000000000..e9a428d4e7
--- /dev/null
+++ b/tests/integration/pull_auto_merge_test.go
@@ -0,0 +1,106 @@
+// Copyright 2026 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package integration
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"path"
+	"strings"
+	"testing"
+	"time"
+
+	unit_model "forgejo.org/models/unit"
+	"forgejo.org/models/unittest"
+	user_model "forgejo.org/models/user"
+	"forgejo.org/modules/git"
+	app_context "forgejo.org/services/context"
+	files_service "forgejo.org/services/repository/files"
+	"forgejo.org/tests"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestPullRemoveAutomerge(t *testing.T) {
+	onApplicationRun(t, func(t *testing.T, u *url.URL) {
+		user5 := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 5})
+		user5Session := loginUser(t, user5.Name)
+		user2Session := loginUser(t, "user2")
+
+		repo, _, f := tests.CreateDeclarativeRepo(t, user5, "",
+			[]unit_model.Type{unit_model.TypeCode, unit_model.TypePullRequests}, nil,
+			[]*files_service.ChangeRepoFile{
+				{
+					Operation: "create",
+					TreePath:  "FUNFACT",
+					ContentReader: strings.NewReader(
+						"The Netherlands got its first openly gay prime minister today."),
+				},
+			},
+		)
+		defer f()
+
+		dstPath := t.TempDir()
+		cloneURL, _ := url.Parse(fmt.Sprintf("%suser5/%s.git", u.String(), repo.Name))
+		cloneURL.User = url.UserPassword("user5", userPassword)
+		require.NoError(t, git.CloneWithArgs(t.Context(), nil, cloneURL.String(), dstPath, git.CloneRepoOptions{}))
+		doGitSetRemoteURL(dstPath, "origin", cloneURL)(t)
+
+		require.NoError(t, git.NewCommand(t.Context(), "switch", "-c", "new-fun-fact").Run(&git.RunOpts{Dir: dstPath}))
+
+		require.NoError(t, os.WriteFile(path.Join(dstPath, "README.md"), []byte("The house of representative already had that in 1937."), 0o600))
+		require.NoError(t, git.AddChanges(dstPath, true))
+		require.NoError(t, git.CommitChanges(dstPath, git.CommitChangesOptions{
+			Committer: &git.Signature{
+				Email: "user2@example.com",
+				Name:  "user2",
+				When:  time.Now(),
+			},
+			Author: &git.Signature{
+				Email: "user2@example.com",
+				Name:  "user2",
+				When:  time.Now(),
+			},
+			Message: "Update funfact.",
+		}))
+
+		require.NoError(t, git.NewCommand(t.Context(), "push", "origin", "HEAD:refs/for/main", "-o", "topic=new-fun-fact").Run(&git.RunOpts{Dir: dstPath}))
+
+		// Create a protected branch rule for automerge.
+		user5Session.MakeRequest(t, NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/settings/branches/edit", repo.FullName()), map[string]string{
+			"rule_name":          "main",
+			"required_approvals": "1",
+		}), http.StatusSeeOther)
+
+		// Start a automerge for new pull request.
+		user5Session.MakeRequest(t, NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/pulls/1/merge", repo.FullName()), map[string]string{
+			"merge_message_field":       "I love automation when it works",
+			"do":                        "merge",
+			"merge_when_checks_succeed": "true",
+		}), http.StatusOK)
+
+		t.Run("No permission", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			user2Session.MakeRequest(t, NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/pulls/1/cancel_auto_merge", repo.FullName()), nil), http.StatusSeeOther)
+
+			flashCookie := user2Session.GetCookie(app_context.CookieNameFlash)
+			assert.NotNil(t, flashCookie)
+			assert.Equal(t, "error%3DYou%2Bdo%2Bnot%2Bhave%2Bpermission%2Bto%2Bcancel%2Bthis%2Bpull%2Brequest%2527s%2Bauto%2Bmerge.", flashCookie.Value)
+		})
+
+		t.Run("Normal", func(t *testing.T) {
+			defer tests.PrintCurrentTest(t)()
+
+			user5Session.MakeRequest(t, NewRequestWithValues(t, "POST", fmt.Sprintf("/%s/pulls/1/cancel_auto_merge", repo.FullName()), nil), http.StatusSeeOther)
+
+			flashCookie := user5Session.GetCookie(app_context.CookieNameFlash)
+			assert.NotNil(t, flashCookie)
+			assert.Equal(t, "success%3DThe%2Bauto%2Bmerge%2Bwas%2Bcanceled%2Bfor%2Bthis%2Bpull%2Brequest.", flashCookie.Value)
+		})
+	})
+}