diff --git a/doc/api_reference.py b/doc/api_reference.py
index 8952078881122..b7bbeb3d3643f 100644
--- a/doc/api_reference.py
+++ b/doc/api_reference.py
@@ -123,7 +123,6 @@ def _get_submodule(module_name, submodule_name):
                     "is_classifier",
                     "is_clusterer",
                     "is_regressor",
-                    "is_transformer",
                     "is_outlier_detector",
                 ],
             }
diff --git a/doc/whats_new/upcoming_changes/sklearn.base/30122.api.rst b/doc/whats_new/upcoming_changes/sklearn.base/30122.api.rst
index 1ca6052340930..1acfce3aeda5c 100644
--- a/doc/whats_new/upcoming_changes/sklearn.base/30122.api.rst
+++ b/doc/whats_new/upcoming_changes/sklearn.base/30122.api.rst
@@ -1,5 +1,5 @@
 - Passing a class object to :func:`~sklearn.base.is_classifier`,
-  :func:`~sklearn.base.is_regressor`, :func:`~sklearn.base.is_transformer`, and
+  :func:`~sklearn.base.is_regressor`, and
   :func:`~sklearn.base.is_outlier_detector` is now deprecated. Pass an instance
   instead.
   By `Adrin Jalali`_