diff --git a/Packages/cornerstone/client/cornerstoneTools.js b/Packages/cornerstone/client/cornerstoneTools.js
index 31d2a7893..49b5b9763 100644
--- a/Packages/cornerstone/client/cornerstoneTools.js
+++ b/Packages/cornerstone/client/cornerstoneTools.js
@@ -7731,6 +7731,14 @@ if (typeof cornerstoneTools === 'undefined') {
             return;
         }
 
+        var activeViewportIndex = Session.get('activeViewport');
+        var viewportIndex = $('.imageViewerViewport').index(referenceElement);
+
+        //  Only show reference lines in relation to the active viewport
+        if (viewportIndex != activeViewportIndex) {
+            return;
+        }
+
         var targetImagePlane = cornerstoneTools.metaData.get('imagePlane', targetImage.imageId);
         var referenceImagePlane = cornerstoneTools.metaData.get('imagePlane', referenceImage.imageId);