diff --git a/src/lib.rs b/src/lib.rs
index 3e3b0a007..6b95739c5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -353,6 +353,9 @@ $     the end of text (or end-of-line with multi-line mode)
 \B    not a Unicode word boundary
 </pre>
 
+The empty regex is valid and matches the empty string. For example, the empty
+regex matches `abc` at positions `0`, `1`, `2` and `3`.
+
 ## Grouping and flags
 
 <pre class="rust">