diff --git a/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js b/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js
index 3c98443e811b..ead095800a2d 100644
--- a/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js
+++ b/extensions/amp-ad-network-doubleclick-impl/0.1/amp-ad-network-doubleclick-impl.js
@@ -1250,7 +1250,16 @@ export class AmpAdNetworkDoubleclickImpl extends AmpA4A {
       (returnedSizeDifferent && heightNotIncreased)
     ) {
       this.attemptChangeSize(newHeight, newWidth).catch(() => {});
-      if (newWidth > width) {
+      if (
+        newWidth > width &&
+        // If 'fluid' were the primary requested size, ensure we do not trigger
+        // slot adjustment if the returned size is one of the requested multi-
+        // sizes. Slot adjustment should only be triggered when the creative
+        // size is not one of the requested sizes.
+        (!this.isFluidPrimaryRequest_ ||
+          (this.parameterSize &&
+            this.parameterSize.indexOf(`${newWidth}x${newHeight}`) == -1))
+      ) {
         this.adjustSlotPostExpansion_(newWidth);
       }
     }
diff --git a/extensions/amp-ad-network-doubleclick-impl/0.1/test/test-amp-ad-network-doubleclick-impl.js b/extensions/amp-ad-network-doubleclick-impl/0.1/test/test-amp-ad-network-doubleclick-impl.js
index a5429033ff1f..4e783abcfcfa 100644
--- a/extensions/amp-ad-network-doubleclick-impl/0.1/test/test-amp-ad-network-doubleclick-impl.js
+++ b/extensions/amp-ad-network-doubleclick-impl/0.1/test/test-amp-ad-network-doubleclick-impl.js
@@ -355,8 +355,21 @@ describes.realWin('amp-ad-network-doubleclick-impl', realWinConfig, env => {
         newWidth: 400,
         margin: '-375px',
       },
+      {
+        direction: 'ltr',
+        parentWidth: 300,
+        newWidth: 200,
+        margin: '',
+        isMultiSizeResponse: true,
+      },
     ].forEach((testCase, testNum) => {
       it(`should adjust slot CSS after expanding width #${testNum}`, () => {
+        if (testCase.isMultiSizeResponse) {
+          impl.parameterSize = '320x50,200x50';
+          impl.isFluidPrimaryRequest_ = true;
+        } else {
+          impl.paramterSize = '200x50';
+        }
         sandbox.stub(impl, 'attemptChangeSize').callsFake((height, width) => {
           impl.element.style.width = `${width}px`;
           return {
@@ -390,8 +403,10 @@ describes.realWin('amp-ad-network-doubleclick-impl', realWinConfig, env => {
           },
         });
         expect(impl.element.style[`margin${dirStr}`]).to.equal(testCase.margin);
-        // We use a fixed '11' value for z-index.
-        expect(impl.element.style.zIndex).to.equal('11');
+        if (!testCase.isMultiSizeResponse) {
+          // We use a fixed '11' value for z-index.
+          expect(impl.element.style.zIndex).to.equal('11');
+        }
       });
     });
   });