diff --git a/README.md b/README.md
index f77af56..1b6fd0a 100644
--- a/README.md
+++ b/README.md
@@ -189,6 +189,10 @@ settings = {
 },
 ```
 
+### Highlight Groups
+Currently available highlight groups are
+`HarpoonWindow`, `HarpoonBorder`, and `HarpoonTitle`.
+
 ## ⇁ Contribution
 This project is officially open source, not just public source.  If you wish to
 contribute start with an issue and I am totally willing for PRs, but I will be