diff --git a/doc/source/whatsnew/v0.25.0.rst b/doc/source/whatsnew/v0.25.0.rst
index c441244b4415d..349c7852a0541 100644
--- a/doc/source/whatsnew/v0.25.0.rst
+++ b/doc/source/whatsnew/v0.25.0.rst
@@ -375,7 +375,6 @@ Plotting
 Groupby/Resample/Rolling
 ^^^^^^^^^^^^^^^^^^^^^^^^
 
-- Bug in :meth:`pandas.core.resample.Resampler.agg` with a timezone aware index where ``OverflowError`` would raise when passing a list of functions (:issue:`22660`)
 - Bug in :meth:`pandas.core.groupby.DataFrameGroupBy.nunique` in which the names of column levels were lost (:issue:`23222`)
 - Bug in :func:`pandas.core.groupby.GroupBy.agg` when applying a aggregation function to timezone aware data (:issue:`23683`)
 - Bug in :func:`pandas.core.groupby.GroupBy.first` and :func:`pandas.core.groupby.GroupBy.last` where timezone information would be dropped (:issue:`21603`)
@@ -384,6 +383,7 @@ Groupby/Resample/Rolling
 - Ensured that result group order is correct when grouping on an ordered ``Categorical`` and specifying ``observed=True`` (:issue:`25871`, :issue:`25167`)
 - Bug in :meth:`pandas.core.window.Rolling.min` and :meth:`pandas.core.window.Rolling.max` that caused a memory leak (:issue:`25893`)
 - Bug in :func:`idxmax` and :func:`idxmin` on :meth:`DataFrame.groupby` with datetime column would return incorrect dtype (:issue:`25444`, :issue:`15306`)
+- Bug in ::meth:`pandas.core.groupby.GroupBy.aggwhen passingas_index=False``, returning an additional column.
 
 Reshaping
 ^^^^^^^^^
diff --git a/pandas/core/base.py b/pandas/core/base.py
index 9a0a4e3e9ca03..6a959e50f8aeb 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -559,7 +559,7 @@ def is_any_frame():
             # we require a list, but not an 'str'
             return self._aggregate_multiple_funcs(arg,
                                                   _level=_level,
-                                                  _axis=_axis), None
+                                                  _axis=_axis), True
         else:
             result = None
 
diff --git a/pandas/tests/groupby/aggregate/test_aggregate.py b/pandas/tests/groupby/aggregate/test_aggregate.py
index ae8ed8db0aa5d..dba732ae3af60 100644
--- a/pandas/tests/groupby/aggregate/test_aggregate.py
+++ b/pandas/tests/groupby/aggregate/test_aggregate.py
@@ -288,6 +288,40 @@ def test_multi_function_flexible_mix(df):
     tm.assert_frame_equal(result, expected)
 
 
+@pytest.mark.parametrize('as_index', [True, False])
+def test_not_as_index_agg_list(as_index):
+
+    # GH 25011
+    array = [[3, 1, 2],
+             [3, 3, 4],
+             [4, 5, 6],
+             [4, 7, 8]]
+    df = pd.DataFrame(array, columns=['index_iff_as_index', 'A', 'B'])
+    groupby = df.groupby('index_iff_as_index', as_index=as_index)
+    result = groupby.agg(['min', 'max'])
+
+    if as_index:
+
+        array2 = [[1, 3, 2, 4],
+                  [5, 7, 6, 8]]
+        columns = pd.MultiIndex(levels=[['A', 'B'],
+                                        ['min', 'max']],
+                                codes=[[0, 0, 1, 1], [0, 1, 0, 1]])
+        index = pd.Series([3, 4], name='index_iff_as_index')
+        expected = pd.DataFrame(array2, columns=columns, index=index)
+
+    else:
+
+        array2 = [[3, 1, 3, 2, 4],
+                  [4, 5, 7, 6, 8]]
+        columns = pd.MultiIndex(levels=[['A', 'B', 'index_iff_as_index'],
+                                        ['min', 'max', '']],
+                                codes=[[2, 0, 0, 1, 1], [2, 0, 1, 0, 1]])
+        expected = pd.DataFrame(array2, columns=columns)
+
+    tm.assert_frame_equal(result, expected)
+
+
 def test_groupby_agg_coercing_bools():
     # issue 14873
     dat = pd.DataFrame(