BUG: read_excel forward-filling MI names

doc/source/whatsnew/v1.3.0.rst

@@ -241,6 +241,7 @@ I/O
 - Bug in :func:`read_csv` not accepting ``usecols`` with different length than ``names`` for ``engine="python"`` (:issue:`16469`)
 - Bug in :func:`read_csv` raising ``TypeError`` when ``names`` and ``parse_dates`` is specified for ``engine="c"`` (:issue:`33699`)
 - Allow custom error values for parse_dates argument of :func:`read_sql`, :func:`read_sql_query` and :func:`read_sql_table` (:issue:`35185`)
+- Bug in :func:`read_excel` forward filling :class:`MultiIndex` names with multiple header and index columns specified (:issue:`34673`)
 -
 
 Period

pandas/io/excel/_base.py

@@ -503,6 +503,8 @@ def parse(
                         header_name, _ = pop_header_name(data[row], index_col)
                         header_names.append(header_name)
 
+            has_index_names = is_list_like(header) and len(header) > 1
+
             if is_list_like(index_col):
                 # Forward fill values for MultiIndex index.
                 if header is None:
@@ -512,6 +514,11 @@ def parse(
                 else:
                     offset = 1 + max(header)
 
+                # GH34673: if MultiIndex names present and not defined in the header,
+                # don't forward fill the names
+                if has_index_names:
+                    offset += 1
+
                 # Check if we have an empty dataset
                 # before trying to collect data.
                 if offset < len(data):
@@ -524,8 +531,6 @@ def parse(
                             else:
                                 last = data[row][col]
 
-            has_index_names = is_list_like(header) and len(header) > 1
-
             # GH 12292 : error when read one empty column from excel file
             try:
                 parser = TextParser(

pandas/tests/io/excel/test_readers.py

@@ -804,6 +804,19 @@ def test_read_excel_multiindex(self, read_ext):
         )
         tm.assert_frame_equal(actual, expected)
 
+        # GH34673: "both_name_blank_after_mi_name" sheet
+        expected.index = MultiIndex.from_tuples(
+            [("foo", np.nan), ("foo", "b"), ("bar", "a"), ("bar", "b")],
+            names=["ilvl1", "ilvl2"],
+        )
+        actual = pd.read_excel(
+            mi_file,
+            sheet_name="both_name_blank_after_mi_name",
+            index_col=[0, 1],
+            header=[0, 1],
+        )
+        tm.assert_frame_equal(actual, expected)
+
     def test_read_excel_multiindex_header_only(self, read_ext):
         # see gh-11733.
         #