diff --git a/docs/reference/ImageShow.rst b/docs/reference/ImageShow.rst
index e4d9805ab4c..45b50c8469b 100644
--- a/docs/reference/ImageShow.rst
+++ b/docs/reference/ImageShow.rst
@@ -17,6 +17,7 @@ All default viewers convert the image to be shown to PNG format.
 
     The following viewers may be registered on Unix-based systems, if the given command is found:
 
+    .. autoclass:: PIL.ImageShow.XDGViewer
     .. autoclass:: PIL.ImageShow.DisplayViewer
     .. autoclass:: PIL.ImageShow.GmDisplayViewer
     .. autoclass:: PIL.ImageShow.EogViewer