diff --git a/roboticstoolbox/robot/ERobot.py b/roboticstoolbox/robot/ERobot.py
index c73b2f797..53929dbe9 100644
--- a/roboticstoolbox/robot/ERobot.py
+++ b/roboticstoolbox/robot/ERobot.py
@@ -760,7 +760,7 @@ def dotfile(self, filename, etsbox=False, jtype=False, static=True):
         :seealso: :func:`showgraph`
         """
         if isinstance(filename, str):
-            file = open(filename, 'w')
+            file = open(filename, 'w', encoding='utf-8')
         else:
             file = filename