diff --git a/src/MountedTraversal.js b/src/MountedTraversal.js
index afeb9650c..2e96561cb 100644
--- a/src/MountedTraversal.js
+++ b/src/MountedTraversal.js
@@ -51,8 +51,9 @@ export function instHasClassName(inst, className) {
   if (!isDOMComponent(inst)) {
     return false;
   }
-  const classes = findDOMNode(inst).className || '';
-  return ` ${classes.trim()} `.indexOf(` ${className} `) > -1;
+  let classes = findDOMNode(inst).className || '';
+  classes = classes.replace(/\s/g, ' ').trim();
+  return ` ${classes} `.indexOf(` ${className} `) > -1;
 }
 
 export function instHasId(inst, id) {
diff --git a/src/ShallowTraversal.js b/src/ShallowTraversal.js
index 0a52ef7b6..6a8a9142a 100644
--- a/src/ShallowTraversal.js
+++ b/src/ShallowTraversal.js
@@ -28,8 +28,9 @@ export function childrenOfNode(node) {
 }
 
 export function hasClassName(node, className) {
-  const classes = propsOfNode(node).className || '';
-  return ` ${classes.trim()} `.indexOf(` ${className} `) > -1;
+  let classes = propsOfNode(node).className || '';
+  classes = classes.replace(/\s/g, ' ').trim();
+  return ` ${classes} `.indexOf(` ${className} `) > -1;
 }
 
 export function treeForEach(tree, fn) {
diff --git a/test/ReactWrapper-spec.js b/test/ReactWrapper-spec.js
index 0b0da382f..a01e33a1f 100644
--- a/test/ReactWrapper-spec.js
+++ b/test/ReactWrapper-spec.js
@@ -901,12 +901,20 @@ describeWithDOM('mount', () => {
     });
 
     it('should ignore insignificant whitespace', () => {
-      const className = `foo
+      const className = `
+      foo
       `;
       const wrapper = mount(<div className={className} />);
       expect(wrapper.is('.foo')).to.equal(true);
     });
 
+    it('should handle all significant whitespace', () => {
+      const className = `foo  bar
+      baz`;
+      const wrapper = mount(<div className={className} />);
+      expect(wrapper.is('.foo.bar.baz')).to.equal(true);
+    });
+
     it('should return false when selector does not match', () => {
       const wrapper = mount(<div className="bar baz" />);
       expect(wrapper.is('.foo')).to.equal(false);
diff --git a/test/ShallowWrapper-spec.js b/test/ShallowWrapper-spec.js
index c074d0e15..05c924fd5 100644
--- a/test/ShallowWrapper-spec.js
+++ b/test/ShallowWrapper-spec.js
@@ -1014,6 +1014,13 @@ describe('shallow', () => {
       expect(wrapper.is('.foo')).to.equal(true);
     });
 
+    it('should handle all significant whitespace', () => {
+      const className = `foo  bar
+      baz`;
+      const wrapper = shallow(<div className={className} />);
+      expect(wrapper.is('.foo.bar.baz')).to.equal(true);
+    });
+
     it('should return false when selector does not match', () => {
       const wrapper = shallow(<div className="bar baz" />);
       expect(wrapper.is('.foo')).to.equal(false);