diff --git a/doc/cc65.sgml b/doc/cc65.sgml
index dc754cb31..ae80b11b0 100644
--- a/doc/cc65.sgml
+++ b/doc/cc65.sgml
@@ -563,6 +563,8 @@ Here is a description of all the command line options:
         Warn about #pragmas that aren't recognized by cc65.
   <tag><tt/unreachable-code/</tag>
         Warn about unreachable code in cases of comparing constants, etc.
+  <tag><tt/unused-func/</tag>
+        Warn about unused functions.
   <tag><tt/unused-label/</tag>
         Warn about unused labels.
   <tag><tt/unused-param/</tag>