diff --git a/doc/source/whatsnew/v3.0.0.rst b/doc/source/whatsnew/v3.0.0.rst
index 278971ef88a0f..eb078e1f18f7a 100644
--- a/doc/source/whatsnew/v3.0.0.rst
+++ b/doc/source/whatsnew/v3.0.0.rst
@@ -254,6 +254,7 @@ Removal of prior version deprecations/changes
 - Enforced deprecation of :meth:`offsets.Tick.delta`, use ``pd.Timedelta(obj)`` instead (:issue:`55498`)
 - Enforced deprecation of ``axis=None`` acting the same as ``axis=0`` in the DataFrame reductions ``sum``, ``prod``, ``std``, ``var``, and ``sem``, passing ``axis=None`` will now reduce over both axes; this is particularly the case when doing e.g. ``numpy.sum(df)`` (:issue:`21597`)
 - Enforced deprecation of ``core.internals`` members ``Block``, ``ExtensionBlock``, and ``DatetimeTZBlock`` (:issue:`58467`)
+- Enforced deprecation of ``quantile`` keyword in :meth:`.Rolling.quantile` and :meth:`.Expanding.quantile`, renamed to ``q`` instead. (:issue:`52550`)
 - Enforced deprecation of non-standard (``np.ndarray``, :class:`ExtensionArray`, :class:`Index`, or :class:`Series`) argument to :func:`api.extensions.take` (:issue:`52981`)
 - Enforced deprecation of parsing system timezone strings to ``tzlocal``, which depended on system timezone, pass the 'tz' keyword instead (:issue:`50791`)
 - Enforced deprecation of passing a dictionary to :meth:`SeriesGroupBy.agg` (:issue:`52268`)
diff --git a/pandas/core/window/expanding.py b/pandas/core/window/expanding.py
index abe853a8aa259..f14954cd9a4b0 100644
--- a/pandas/core/window/expanding.py
+++ b/pandas/core/window/expanding.py
@@ -8,10 +8,7 @@
     Literal,
 )
 
-from pandas.util._decorators import (
-    deprecate_kwarg,
-    doc,
-)
+from pandas.util._decorators import doc
 
 from pandas.core.indexers.objects import (
     BaseIndexer,
@@ -709,7 +706,6 @@ def kurt(self, numeric_only: bool = False):
         aggregation_description="quantile",
         agg_method="quantile",
     )
-    @deprecate_kwarg(old_arg_name="quantile", new_arg_name="q")
     def quantile(
         self,
         q: float,
diff --git a/pandas/core/window/rolling.py b/pandas/core/window/rolling.py
index db6078ae636e3..2243d8dd1a613 100644
--- a/pandas/core/window/rolling.py
+++ b/pandas/core/window/rolling.py
@@ -27,10 +27,7 @@
 import pandas._libs.window.aggregations as window_aggregations
 from pandas.compat._optional import import_optional_dependency
 from pandas.errors import DataError
-from pandas.util._decorators import (
-    deprecate_kwarg,
-    doc,
-)
+from pandas.util._decorators import doc
 
 from pandas.core.dtypes.common import (
     ensure_float64,
@@ -2556,7 +2553,6 @@ def kurt(self, numeric_only: bool = False):
         aggregation_description="quantile",
         agg_method="quantile",
     )
-    @deprecate_kwarg(old_arg_name="quantile", new_arg_name="q")
     def quantile(
         self,
         q: float,
diff --git a/pandas/tests/window/test_expanding.py b/pandas/tests/window/test_expanding.py
index 1c7bcb8493bc1..b4a045cd26fe4 100644
--- a/pandas/tests/window/test_expanding.py
+++ b/pandas/tests/window/test_expanding.py
@@ -691,12 +691,3 @@ def test_numeric_only_corr_cov_series(kernel, use_arg, numeric_only, dtype):
         op2 = getattr(expanding2, kernel)
         expected = op2(*arg2, numeric_only=numeric_only)
         tm.assert_series_equal(result, expected)
-
-
-def test_keyword_quantile_deprecated():
-    # GH #52550
-    ser = Series([1, 2, 3, 4])
-    with tm.assert_produces_warning(
-        FutureWarning, match="the 'quantile' keyword is deprecated, use 'q' instead"
-    ):
-        ser.expanding().quantile(quantile=0.5)
diff --git a/pandas/tests/window/test_rolling_quantile.py b/pandas/tests/window/test_rolling_quantile.py
index 1604d72d4f9b1..66713f1cfaa8d 100644
--- a/pandas/tests/window/test_rolling_quantile.py
+++ b/pandas/tests/window/test_rolling_quantile.py
@@ -173,12 +173,3 @@ def test_center_reindex_frame(frame, q):
     )
     frame_rs = frame.rolling(window=25, center=True).quantile(q)
     tm.assert_frame_equal(frame_xp, frame_rs)
-
-
-def test_keyword_quantile_deprecated():
-    # GH #52550
-    s = Series([1, 2, 3, 4])
-    with tm.assert_produces_warning(
-        FutureWarning, match="the 'quantile' keyword is deprecated, use 'q' instead"
-    ):
-        s.rolling(2).quantile(quantile=0.4)