diff --git a/src/rmodels.c b/src/rmodels.c
index 166f51a6a..9c57d991b 100644
--- a/src/rmodels.c
+++ b/src/rmodels.c
@@ -3584,8 +3584,8 @@ void DrawBillboardRec(Camera camera, Texture2D texture, Rectangle source, Vector
 
 void DrawBillboardPro(Camera camera, Texture2D texture, Rectangle source, Vector3 position, Vector3 up, Vector2 size, Vector2 origin, float rotation, Color tint)
 {
-    // NOTE: Billboard size will maintain source rectangle aspect ratio, size will represent billboard width
-    Vector2 sizeRatio = { size.x*fabsf((float)source.width/source.height), size.y };
+    // NOTE: Billboard size will maintain source rectangle aspect ratio, so "size.x" is effectively ignored.
+    Vector2 sizeRatio = { size.y * fabsf((float)source.width/source.height), size.y };
 
     Matrix matView = MatrixLookAt(camera.position, camera.target, camera.up);