diff --git a/src/ol/geom/SimpleGeometry.js b/src/ol/geom/SimpleGeometry.js
index 1f8b244694..7119ebd5d9 100644
--- a/src/ol/geom/SimpleGeometry.js
+++ b/src/ol/geom/SimpleGeometry.js
@@ -217,7 +217,7 @@ class SimpleGeometry extends Geometry {
   /**
    * Rotate the geometry around a given coordinate. This modifies the geometry
    * coordinates in place.
-   * @param {number} angle Rotation angle in radians.
+   * @param {number} angle Rotation angle in counter-clockwise radians.
    * @param {import("../coordinate.js").Coordinate} anchor The rotation center.
    * @api
    */