diff --git a/apidoc/readme.md b/apidoc/readme.md
index 94a4e68f65..21acb60ff9 100644
--- a/apidoc/readme.md
+++ b/apidoc/readme.md
@@ -72,3 +72,6 @@ ol.Map = function(options) {
 };
 ```
 
+### Observable Properties
+
+Observable properties are documented using the `@observable` annotation. This annotation is added to the getter of an observable property. If an observable property is also settable, the setter is annotated with `@observable` as well.