diff --git a/tests/examples_arguments_syntax/bump_chart.py b/tests/examples_arguments_syntax/bump_chart.py
index 102784590..1586b956e 100644
--- a/tests/examples_arguments_syntax/bump_chart.py
+++ b/tests/examples_arguments_syntax/bump_chart.py
@@ -12,7 +12,7 @@
 import pandas as pd
 
 stocks = data.stocks()
-source = stocks.groupby([pd.Grouper(key="date", freq="6ME"),"symbol"]).mean().reset_index()
+source = stocks.groupby([pd.Grouper(key="date", freq="6M"),"symbol"]).mean().reset_index()
 
 alt.Chart(source).mark_line(point = True).encode(
     x = alt.X("date:O", timeUnit="yearmonth", title="date"),
diff --git a/tests/examples_methods_syntax/bump_chart.py b/tests/examples_methods_syntax/bump_chart.py
index 0c31b06e7..03f88c8ac 100644
--- a/tests/examples_methods_syntax/bump_chart.py
+++ b/tests/examples_methods_syntax/bump_chart.py
@@ -12,7 +12,7 @@
 import pandas as pd
 
 stocks = data.stocks()
-source = stocks.groupby([pd.Grouper(key="date", freq="6ME"),"symbol"]).mean().reset_index()
+source = stocks.groupby([pd.Grouper(key="date", freq="6M"),"symbol"]).mean().reset_index()
 
 alt.Chart(source).mark_line(point=True).encode(
     x=alt.X("date:O").timeUnit("yearmonth").title("date"),
diff --git a/tests/utils/test_utils.py b/tests/utils/test_utils.py
index 425d2297d..aa49e9369 100644
--- a/tests/utils/test_utils.py
+++ b/tests/utils/test_utils.py
@@ -46,11 +46,11 @@ def test_sanitize_dataframe():
             "f": np.arange(5, dtype=float),
             "i": np.arange(5, dtype=int),
             "b": np.array([True, False, True, True, False]),
-            "d": pd.date_range("2012-01-01", periods=5, freq="h"),
+            "d": pd.date_range("2012-01-01", periods=5, freq="H"),
             "c": pd.Series(list("ababc"), dtype="category"),
             "c2": pd.Series([1, "A", 2.5, "B", None], dtype="category"),
             "o": pd.Series([np.array(i) for i in range(5)]),
-            "p": pd.date_range("2012-01-01", periods=5, freq="h").tz_localize("UTC"),
+            "p": pd.date_range("2012-01-01", periods=5, freq="H").tz_localize("UTC"),
         }
     )
 
@@ -98,9 +98,9 @@ def test_sanitize_dataframe_arrow_columns():
             "f": np.arange(5, dtype=float),
             "i": np.arange(5, dtype=int),
             "b": np.array([True, False, True, True, False]),
-            "d": pd.date_range("2012-01-01", periods=5, freq="h"),
+            "d": pd.date_range("2012-01-01", periods=5, freq="H"),
             "c": pd.Series(list("ababc"), dtype="category"),
-            "p": pd.date_range("2012-01-01", periods=5, freq="h").tz_localize("UTC"),
+            "p": pd.date_range("2012-01-01", periods=5, freq="H").tz_localize("UTC"),
         }
     )
     df_arrow = pa.Table.from_pandas(df).to_pandas(types_mapper=pd.ArrowDtype)
diff --git a/tests/vegalite/v5/test_api.py b/tests/vegalite/v5/test_api.py
index 4e62ac46a..c0d70d0ac 100644
--- a/tests/vegalite/v5/test_api.py
+++ b/tests/vegalite/v5/test_api.py
@@ -115,7 +115,7 @@ def Chart(data):
 def test_chart_infer_types():
     data = pd.DataFrame(
         {
-            "x": pd.date_range("2012", periods=10, freq="YE"),
+            "x": pd.date_range("2012", periods=10, freq="Y"),
             "y": range(10),
             "c": list("abcabcabca"),
             "s": pd.Categorical([1, 2] * 5, categories=[2, 1], ordered=True),
@@ -220,7 +220,7 @@ def test_multiple_encodings(args, kwargs):
 def test_chart_operations():
     data = pd.DataFrame(
         {
-            "x": pd.date_range("2012", periods=10, freq="YE"),
+            "x": pd.date_range("2012", periods=10, freq="Y"),
             "y": range(10),
             "c": list("abcabcabca"),
         }