diff --git a/CODE_STYLE.md b/CODE_STYLE.md
index 0c00a15a5..a5beeb971 100644
--- a/CODE_STYLE.md
+++ b/CODE_STYLE.md
@@ -61,3 +61,9 @@ Any exception or additions specific to our project are documented below.
 
   Some standards (e.g. ERC20) use present tense, and in those cases the
   standard specification prevails.
+  
+* Interface names should have a capital I prefix.
+
+    ```
+    interface IERC777 {
+    ```