diff --git a/doc/source/whatsnew/v1.4.1.rst b/doc/source/whatsnew/v1.4.1.rst
index 9509b96055255..9c813a4803004 100644
--- a/doc/source/whatsnew/v1.4.1.rst
+++ b/doc/source/whatsnew/v1.4.1.rst
@@ -31,7 +31,7 @@ Bug fixes
 - Fixed segfault in :meth:``DataFrame.to_json`` when dumping tz-aware datetimes in Python 3.10 (:issue:`42130`)
 - Stopped emitting unnecessary ``FutureWarning`` in :meth:`DataFrame.sort_values` with sparse columns (:issue:`45618`)
 - Fixed window aggregations in :meth:`DataFrame.rolling` and :meth:`Series.rolling` to skip over unused elements (:issue:`45647`)
--
+- Bug in :func:`api.types.is_bool_dtype` was raising an ``AttributeError`` when evaluating a categorical :class:`Series` (:issue:`45615`)
 
 .. ---------------------------------------------------------------------------
 
diff --git a/pandas/core/dtypes/common.py b/pandas/core/dtypes/common.py
index 109073c7511d0..6776064342db0 100644
--- a/pandas/core/dtypes/common.py
+++ b/pandas/core/dtypes/common.py
@@ -1319,7 +1319,7 @@ def is_bool_dtype(arr_or_dtype) -> bool:
         return False
 
     if isinstance(dtype, CategoricalDtype):
-        arr_or_dtype = arr_or_dtype.categories
+        arr_or_dtype = dtype.categories
         # now we use the special definition for Index
 
     if isinstance(arr_or_dtype, ABCIndex):
diff --git a/pandas/tests/dtypes/test_common.py b/pandas/tests/dtypes/test_common.py
index 165873186aa5a..a32b37fbdd71b 100644
--- a/pandas/tests/dtypes/test_common.py
+++ b/pandas/tests/dtypes/test_common.py
@@ -562,12 +562,14 @@ def test_is_bool_dtype():
     assert not com.is_bool_dtype(int)
     assert not com.is_bool_dtype(str)
     assert not com.is_bool_dtype(pd.Series([1, 2]))
+    assert not com.is_bool_dtype(pd.Series(["a", "b"], dtype="category"))
     assert not com.is_bool_dtype(np.array(["a", "b"]))
     assert not com.is_bool_dtype(pd.Index(["a", "b"]))
     assert not com.is_bool_dtype("Int64")
 
     assert com.is_bool_dtype(bool)
     assert com.is_bool_dtype(np.bool_)
+    assert com.is_bool_dtype(pd.Series([True, False], dtype="category"))
     assert com.is_bool_dtype(np.array([True, False]))
     assert com.is_bool_dtype(pd.Index([True, False]))