diff --git a/CHANGES.rst b/CHANGES.rst
index e5ca2fb1..3e50fe0f 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -8,6 +8,7 @@ Unreleased
     ``importlib.metadata.version("flask")``, instead. :issue:`5230`
 -   Restructure the code such that the Flask (app) and Blueprint
     classes have Sans-IO bases. :pr:`5127`
+-   Allow self as an argument to url_for. :pr:`5264`
 
 
 Version 2.3.3
diff --git a/src/flask/app.py b/src/flask/app.py
index ebb5a202..d710cb96 100644
--- a/src/flask/app.py
+++ b/src/flask/app.py
@@ -952,6 +952,7 @@ class Flask(App):
 
     def url_for(
         self,
+        /,
         endpoint: str,
         *,
         _anchor: str | None = None,
diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index 077cb432..3566385c 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -161,6 +161,13 @@ class TestUrlFor:
         assert flask.url_for("myview", id=42, _method="GET") == "/myview/42"
         assert flask.url_for("myview", _method="POST") == "/myview/create"
 
+    def test_url_for_with_self(self, app, req_ctx):
+        @app.route("/<self>")
+        def index(self):
+            return "42"
+
+        assert flask.url_for("index", self="2") == "/2"
+
 
 def test_redirect_no_app():
     response = flask.redirect("https://localhost", 307)