diff --git a/modules/@angular/common/test/directives/ng_style_spec.ts b/modules/@angular/common/test/directives/ng_style_spec.ts
index 9127d92d68..78e2557524 100644
--- a/modules/@angular/common/test/directives/ng_style_spec.ts
+++ b/modules/@angular/common/test/directives/ng_style_spec.ts
@@ -66,6 +66,41 @@ export function main() {
                  });
            }));
 
+    // keyValueDiffer is sensitive to key order #9115
+    it('should change styles specified in an object expression',
+       inject(
+           [TestComponentBuilder, AsyncTestCompleter],
+           (tcb: TestComponentBuilder, async: AsyncTestCompleter) => {
+             const template = `<div [ngStyle]="expr"></div>`;
+
+             tcb.overrideTemplate(TestComponent, template)
+                 .createAsync(TestComponent)
+                 .then((fixture) => {
+                   fixture.debugElement.componentInstance.expr = {
+                     // height, width order is important here
+                     height: '10px',
+                     width: '10px'
+                   };
+
+                   fixture.detectChanges();
+                   let el = fixture.debugElement.children[0].nativeElement;
+                   expect(getDOM().getStyle(el, 'height')).toEqual('10px');
+                   expect(getDOM().getStyle(el, 'width')).toEqual('10px');
+
+                   fixture.debugElement.componentInstance.expr = {
+                     // width, height order is important here
+                     width: '5px',
+                     height: '5px',
+                   };
+
+                   fixture.detectChanges();
+                   expect(getDOM().getStyle(el, 'height')).toEqual('5px');
+                   expect(getDOM().getStyle(el, 'width')).toEqual('5px');
+
+                   async.done();
+                 });
+           }));
+
     it('should remove styles when deleting a key in an object expression',
        inject(
            [TestComponentBuilder, AsyncTestCompleter],
diff --git a/modules/@angular/core/src/change_detection/differs/default_keyvalue_differ.ts b/modules/@angular/core/src/change_detection/differs/default_keyvalue_differ.ts
index fa5d90540c..5b422ee756 100644
--- a/modules/@angular/core/src/change_detection/differs/default_keyvalue_differ.ts
+++ b/modules/@angular/core/src/change_detection/differs/default_keyvalue_differ.ts
@@ -79,7 +79,7 @@ export class DefaultKeyValueDiffer implements KeyValueDiffer {
       throw new BaseException(`Error trying to diff '${map}'`);
     }
 
-    return this.check(map) ? this : null
+    return this.check(map) ? this : null;
   }
 
   onDestroy() {}
@@ -96,11 +96,7 @@ export class DefaultKeyValueDiffer implements KeyValueDiffer {
       let newSeqRecord: any;
       if (oldSeqRecord && key === oldSeqRecord.key) {
         newSeqRecord = oldSeqRecord;
-        if (!looseIdentical(value, oldSeqRecord.currentValue)) {
-          oldSeqRecord.previousValue = oldSeqRecord.currentValue;
-          oldSeqRecord.currentValue = value;
-          this._addToChanges(oldSeqRecord);
-        }
+        this._maybeAddToChanges(newSeqRecord, value);
       } else {
         seqChanged = true;
         if (oldSeqRecord !== null) {
@@ -109,6 +105,7 @@ export class DefaultKeyValueDiffer implements KeyValueDiffer {
         }
         if (records.has(key)) {
           newSeqRecord = records.get(key);
+          this._maybeAddToChanges(newSeqRecord, value);
         } else {
           newSeqRecord = new KeyValueChangeRecord(key);
           records.set(key, newSeqRecord);
@@ -179,6 +176,14 @@ export class DefaultKeyValueDiffer implements KeyValueDiffer {
     }
   }
 
+  private _maybeAddToChanges(record: KeyValueChangeRecord, newValue: any): void {
+    if (!looseIdentical(newValue, record.currentValue)) {
+      record.previousValue = record.currentValue;
+      record.currentValue = newValue;
+      this._addToChanges(record);
+    }
+  }
+
   /** @internal */
   _isInRemovals(record: KeyValueChangeRecord) {
     return record === this._removalsHead || record._nextRemoved !== null ||
diff --git a/modules/@angular/core/test/change_detection/differs/default_keyvalue_differ_spec.ts b/modules/@angular/core/test/change_detection/differs/default_keyvalue_differ_spec.ts
index 06e78c31af..5054d107fb 100644
--- a/modules/@angular/core/test/change_detection/differs/default_keyvalue_differ_spec.ts
+++ b/modules/@angular/core/test/change_detection/differs/default_keyvalue_differ_spec.ts
@@ -189,11 +189,8 @@ export function main() {
         });
 
         it('should work regardless key order', () => {
-          let m: {[k: string]: number} = {a: 0, b: 0};
-          differ.check(m);
-
-          m = {b: 1, a: 1};
-          differ.check(m);
+          differ.check({a: 0, b: 0});
+          differ.check({b: 1, a: 1});
 
           expect(differ.toString()).toEqual(kvChangesAsString({
             map: ['b[0->1]', 'a[0->1]'],