diff --git a/src/mac/carbon/slider.cpp b/src/mac/carbon/slider.cpp
index 287bfe78ab..f89052de49 100644
--- a/src/mac/carbon/slider.cpp
+++ b/src/mac/carbon/slider.cpp
@@ -252,7 +252,7 @@ void wxSlider::SetLineSize(int lineSize)
 int wxSlider::GetLineSize() const
 {
     // TODO
-    return 0;
+    return m_lineSize;
 }
 
 int wxSlider::GetSelEnd() const