diff --git a/libcorpus2/tag.h b/libcorpus2/tag.h
index 29f59bebf8b986798c2e0108546eb9743399350d..2713071f62976507a6d54b006ac440e776ec200a 100644
--- a/libcorpus2/tag.h
+++ b/libcorpus2/tag.h
@@ -143,10 +143,17 @@ public:
 	bool operator<(const Tag& other) const;
 
 	/**
-	 * Tag equality. Non-equality is provided by Boost template magic.
+	 * Tag equality.
 	 */
 	bool operator==(const Tag& other) const;
 
+	/**
+	 * Tag inequality.
+	 */
+	bool operator!=(const Tag& other) const {
+		return !((*this) == other);
+	}
+
 	/**
 	 * Boost seralization support. Users must include appropriate boost headers.
 	 */