diff --git a/screenplain/richstring.py b/screenplain/richstring.py
index e24db1a..2d75f85 100644
--- a/screenplain/richstring.py
+++ b/screenplain/richstring.py
@@ -116,7 +116,7 @@ def to_html(self):
             re.sub(
                 '  +',  # at least two spaces
                 lambda m: ' ' * (len(m.group(0)) - 1) + ' ',
-                cgi.escape(self.text).encode('ascii', 'xmlcharrefreplace'),
+                cgi.escape(self.text).encode('utf-8', 'xmlcharrefreplace').decode('utf-8'),
             ) +
             ''.join(style.end_html for style in reversed(ordered_styles))
         )