diff --git a/janitor/functions/mutate.py b/janitor/functions/mutate.py
index 0a3b9c2ab..0c5027503 100644
--- a/janitor/functions/mutate.py
+++ b/janitor/functions/mutate.py
@@ -13,7 +13,7 @@
 from janitor.functions.select import get_index_labels
 
 
-@pf.register_groupby_method
+@pf.register_series_groupby_method
 def ungroup(
     df: DataFrameGroupBy,
 ) -> pd.DataFrame:
@@ -58,7 +58,7 @@ def ungroup(
     return df.obj
 
 
-@pf.register_groupby_method
+@pf.register_series_groupby_method
 @pf.register_dataframe_method
 def mutate(
     df: pd.DataFrame | DataFrameGroupBy,
diff --git a/janitor/functions/select.py b/janitor/functions/select.py
index 7b055c2e9..f38613a36 100644
--- a/janitor/functions/select.py
+++ b/janitor/functions/select.py
@@ -344,7 +344,7 @@ def select_rows(
     return _select(df, rows=list(args), invert=invert)
 
 
-@pf.register_groupby_method
+@pf.register_series_groupby_method
 @pf.register_dataframe_method
 @pf.register_series_method
 @deprecated_alias(rows="index")
diff --git a/janitor/functions/summarise.py b/janitor/functions/summarise.py
index 32c612d1c..3abdb6837 100644
--- a/janitor/functions/summarise.py
+++ b/janitor/functions/summarise.py
@@ -14,7 +14,7 @@
 from janitor.functions.select import get_index_labels
 
 
-@pf.register_groupby_method
+@pf.register_series_groupby_method
 @pf.register_dataframe_method
 def summarise(
     df: pd.DataFrame | DataFrameGroupBy,