diff --git a/gramps/plugins/export/exportxml.py b/gramps/plugins/export/exportxml.py
index c91794925..944849834 100644
--- a/gramps/plugins/export/exportxml.py
+++ b/gramps/plugins/export/exportxml.py
@@ -126,7 +126,7 @@ class GrampsXmlWriter(UpdateCallback):
         """
         if filename == '-':
             import sys
-            g = sys.stdout
+            g = sys.stdout.buffer
             self.compress = False
         else:
             base = os.path.dirname(filename)