diff --git a/docs/types/index.rst b/docs/types/index.rst
index 1156b0ce..a49c23e7 100644
--- a/docs/types/index.rst
+++ b/docs/types/index.rst
@@ -10,6 +10,7 @@ Types Reference
    list-and-nonnull
    interfaces
    abstracttypes
+   unions
    objecttypes
    schema
    mutations