diff --git a/index.bs b/index.bs
index f4a82a5dc..86b8b55a3 100644
--- a/index.bs
+++ b/index.bs
@@ -3143,8 +3143,12 @@ that overloaded operations and constructors can be
 specified to take, and in order to describe these restrictions,
 the notion of an <em>effective overload set</em> is used.
 
-[=Operations=] must not be overloaded across [=interface=]
-and [=partial interface=] definitions.
+[=Operations=] must not be overloaded across
+[=interface=],
+[=partial interface=],
+[=mixin=], and
+[=partial mixin=]
+definitions.
 
 <div class="note">