diff --git a/src/compas/geometry/shapes/box.py b/src/compas/geometry/shapes/box.py
index 68be9fcd4cc..a23a564f0e5 100644
--- a/src/compas/geometry/shapes/box.py
+++ b/src/compas/geometry/shapes/box.py
@@ -592,8 +592,8 @@ def scaled(self, x, y=None, z=None):
         """
         box = self.copy()
         box.xsize *= x
-        box.ysize *= y
-        box.zsize *= z
+        box.ysize *= y if y is not None else x
+        box.zsize *= z if z is not None else x
 
         return box