diff --git a/lib/api/attributes.js b/lib/api/attributes.js
index 57b47b6c41..f6d1093d4a 100644
--- a/lib/api/attributes.js
+++ b/lib/api/attributes.js
@@ -332,7 +332,7 @@ var toggleClass = exports.toggleClass = function(value, stateVal) {
     // Check if class already exists
     for (var j = 0; j < numClasses; j++) {
       // Check if the class name is curently defined
-      index = elementClasses.indexOf(classNames[j]);
+      index = !isBool || !stateVal ? elementClasses.indexOf(classNames[j]) : -1;
 
       // Add if stateValue === true or we are toggling and there is no value
       if (isBool ? stateVal : index < 0) {