diff --git a/docs/conf.py b/docs/conf.py
index ec7ac4bdf..7cf8c9fe1 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -40,7 +40,7 @@ extensions = [
     'sphinx.ext.autodoc',
     'sphinx.ext.intersphinx',
     'sphinx.ext.todo',
-    'sphinx.ext.pngmath',
+    'sphinx.ext.imgmath',
     'sphinx.ext.viewcode',
 ]