diff --git a/doc/site/core/index.markdown b/doc/site/core/index.markdown
index 3a2dfe0a..99dd4f49 100644
--- a/doc/site/core/index.markdown
+++ b/doc/site/core/index.markdown
@@ -20,5 +20,6 @@ All Wren source files automatically have access to the following classes:
 * [Range](range.html)
 * [Sequence](sequence.html)
 * [String](string.html)
+* [IO](IO.html)
 
-[embedding]: ../embedding-api.html
\ No newline at end of file
+[embedding]: ../embedding-api.html