diff --git a/pandas/io/excel.py b/pandas/io/excel.py
index f4f40c8be7855..5b612bc4882ee 100644
--- a/pandas/io/excel.py
+++ b/pandas/io/excel.py
@@ -782,6 +782,7 @@ def write_cells(self, cells, sheet_name=None, startrow=0, startcol=0):
             num_format_str = None
             if isinstance(cell.val, datetime.datetime):
                 num_format_str = self.datetime_format
+                cell.val = cell.val.replace(tzinfo=None)
             if isinstance(cell.val, datetime.date):
                 num_format_str = self.date_format