scikit-learn
diff --git a/‎doc/whats_new/v1.3.rst
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diff --git a/‎sklearn/pipeline.py
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diff --git a/‎sklearn/tests/test_pipeline.py
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@@ -36,6 +36,12 @@ Changelog
     :pr:`123456` by :user:`Joe Bloggs <joeongithub>`.
     where 123456 is the *pull request* number, not the issue number.
 
+:mod:`sklearn.pipeline`
+.......................
+- |Feature| :class:`pipeline.FeatureUnion` can now use indexing notation (e.g.
+  `feature_union["scalar"]`) to access transformers by name. :pr:`25093` by
+  `Thomas Fan`_.
+
 Code and Documentation Contributors
 -----------------------------------
 
 
@@ -1286,6 +1286,12 @@ def _sk_visual_block_(self):
         names, transformers = zip(*self.transformer_list)
         return _VisualBlock("parallel", transformers, names=names)
 
+    def __getitem__(self, name):
+        """Return transformer with name."""
+        if not isinstance(name, str):
+            raise KeyError("Only string keys are supported")
+        return self.named_transformers[name]
+
 
 def make_union(*transformers, n_jobs=None, verbose=False):
     """Construct a FeatureUnion from the given transformers.
 
@@ -1658,3 +1658,32 @@ def test_feature_union_set_output():
     assert isinstance(X_trans, pd.DataFrame)
     assert_array_equal(X_trans.columns, union.get_feature_names_out())
     assert_array_equal(X_trans.index, X_test.index)
+
+
+def test_feature_union_getitem():
+    """Check FeatureUnion.__getitem__ returns expected results."""
+    scalar = StandardScaler()
+    pca = PCA()
+    union = FeatureUnion(
+        [
+            ("scalar", scalar),
+            ("pca", pca),
+            ("pass", "passthrough"),
+            ("drop_me", "drop"),
+        ]
+    )
+    assert union["scalar"] is scalar
+    assert union["pca"] is pca
+    assert union["pass"] == "passthrough"
+    assert union["drop_me"] == "drop"
+
+
+@pytest.mark.parametrize("key", [0, slice(0, 2)])
+def test_feature_union_getitem_error(key):
+    """Raise error when __getitem__ gets a non-string input."""
+
+    union = FeatureUnion([("scalar", StandardScaler()), ("pca", PCA())])
+
+    msg = "Only string keys are supported"
+    with pytest.raises(KeyError, match=msg):
+        union[key]