diff --git a/pandas/_typing.py b/pandas/_typing.py
index 2244be1b61fc6..a0578b49d5ecc 100644
--- a/pandas/_typing.py
+++ b/pandas/_typing.py
@@ -35,8 +35,11 @@
     from pandas.core.arrays.base import ExtensionArray  # noqa: F401
     from pandas.core.frame import DataFrame
     from pandas.core.generic import NDFrame  # noqa: F401
+    from pandas.core.groupby.generic import DataFrameGroupBy, SeriesGroupBy
     from pandas.core.indexes.base import Index
+    from pandas.core.resample import Resampler
     from pandas.core.series import Series
+    from pandas.core.window.rolling import BaseWindow
 
     from pandas.io.formats.format import EngFormatter
 
@@ -115,6 +118,14 @@
     List[AggFuncTypeBase],
     AggFuncTypeDict,
 ]
+AggObjType = Union[
+    "Series",
+    "DataFrame",
+    "SeriesGroupBy",
+    "DataFrameGroupBy",
+    "BaseWindow",
+    "Resampler",
+]
 
 
 # for arbitrary kwargs passed during reading/writing files
diff --git a/pandas/core/aggregation.py b/pandas/core/aggregation.py
index ffc3283152687..c64f0bd71cf84 100644
--- a/pandas/core/aggregation.py
+++ b/pandas/core/aggregation.py
@@ -24,6 +24,7 @@
     AggFuncType,
     AggFuncTypeBase,
     AggFuncTypeDict,
+    AggObjType,
     Axis,
     FrameOrSeries,
     FrameOrSeriesUnion,
@@ -530,7 +531,7 @@ def transform_str_or_callable(
 
 
 def aggregate(
-    obj,
+    obj: AggObjType,
     arg: AggFuncType,
     *args,
     **kwargs,
@@ -580,7 +581,7 @@ def aggregate(
 
 
 def agg_list_like(
-    obj,
+    obj: AggObjType,
     arg: List[AggFuncTypeBase],
     _axis: int,
 ) -> FrameOrSeriesUnion:
@@ -672,7 +673,7 @@ def agg_list_like(
 
 
 def agg_dict_like(
-    obj,
+    obj: AggObjType,
     arg: AggFuncTypeDict,
     _axis: int,
 ) -> FrameOrSeriesUnion: