diff --git a/src/MountedTraversal.js b/src/MountedTraversal.js
index ad1b94326..34995c42b 100644
--- a/src/MountedTraversal.js
+++ b/src/MountedTraversal.js
@@ -51,7 +51,8 @@ export function instHasClassName(inst, className) {
   if (!isDOMComponent(inst)) {
     return false;
   }
-  const classes = findDOMNode(inst).className || '';
+  let classes = findDOMNode(inst).className || '';
+  classes = classes.replace(/\s/g, ' ');
   return ` ${classes} `.indexOf(` ${className} `) > -1;
 }
 
diff --git a/src/ShallowTraversal.js b/src/ShallowTraversal.js
index 9d38c8408..2a783f694 100644
--- a/src/ShallowTraversal.js
+++ b/src/ShallowTraversal.js
@@ -28,7 +28,8 @@ export function childrenOfNode(node) {
 }
 
 export function hasClassName(node, className) {
-  const classes = propsOfNode(node).className || '';
+  let classes = propsOfNode(node).className || '';
+  classes = classes.replace(/\s/g, ' ');
   return ` ${classes} `.indexOf(` ${className} `) > -1;
 }
 
diff --git a/test/ReactWrapper-spec.js b/test/ReactWrapper-spec.js
index a8c28124a..9febd1ff2 100644
--- a/test/ReactWrapper-spec.js
+++ b/test/ReactWrapper-spec.js
@@ -900,6 +900,23 @@ describeWithDOM('mount', () => {
       expect(wrapper.is('.foo.bar')).to.equal(true);
     });
 
+    it('should ignore insignificant whitespace', () => {
+      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 475bfb93d..b7e816c36 100644
--- a/test/ShallowWrapper-spec.js
+++ b/test/ShallowWrapper-spec.js
@@ -1007,6 +1007,22 @@ describe('shallow', () => {
       expect(wrapper.is('.foo.bar')).to.equal(true);
     });
 
+    it('should ignore insignificant whitespace', () => {
+      const className = `foo
+      `;
+      const wrapper = shallow(<div className={className} />);
+      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);