diff --git a/src/calibre/ebooks/docx/fonts.py b/src/calibre/ebooks/docx/fonts.py
index 6d766fd3c6..4414ebabe9 100644
--- a/src/calibre/ebooks/docx/fonts.py
+++ b/src/calibre/ebooks/docx/fonts.py
@@ -126,6 +126,8 @@ def do_map(m, points):
 
 def map_symbol_text(text, font):
     m = SYMBOL_MAPS[font]
+    if isinstance(text, bytes):
+        text = text.decode('utf-8')
     return ''.join(do_map(m, ord_string(text)))