diff --git a/packages/@react-aria/utils/src/useViewportSize.ts b/packages/@react-aria/utils/src/useViewportSize.ts
index ed6f6f765e5..b98ae0fc4e9 100644
--- a/packages/@react-aria/utils/src/useViewportSize.ts
+++ b/packages/@react-aria/utils/src/useViewportSize.ts
@@ -57,7 +57,7 @@ export function useViewportSize(): ViewportSize {
         // Wait one frame to see if a new element gets focused.
         frame = requestAnimationFrame(() => {
           if (!document.activeElement || !willOpenKeyboard(document.activeElement)) {
-            updateSize({width: window.innerWidth, height: window.innerHeight});
+            updateSize({width: document.documentElement.clientWidth, height: document.documentElement.clientHeight});
           }
         });
       }
@@ -90,7 +90,7 @@ export function useViewportSize(): ViewportSize {
 function getViewportSize(): ViewportSize {
   return {
     // Multiply by the visualViewport scale to get the "natural" size, unaffected by pinch zooming.
-    width: visualViewport ? visualViewport.width * visualViewport.scale : window.innerWidth,
-    height: visualViewport ? visualViewport.height * visualViewport.scale : window.innerHeight
+    width: visualViewport ? visualViewport.width * visualViewport.scale : document.documentElement.clientWidth,
+    height: visualViewport ? visualViewport.height * visualViewport.scale : document.documentElement.clientHeight
   };
 }
diff --git a/scripts/setupTests.js b/scripts/setupTests.js
index 9565be18aec..fedbf8c0bd3 100644
--- a/scripts/setupTests.js
+++ b/scripts/setupTests.js
@@ -104,8 +104,24 @@ beforeEach(() => {
     disconnect: () => null
   });
   window.IntersectionObserver = mockIntersectionObserver;
+
+  // Set document.documentElement dimensions to match jsdom's default window.innerWidth/innerHeight
+  // This is needed because clientWidth/clientHeight default to 0 in jsdom unless explicitly set
+  Object.defineProperty(document.documentElement, 'clientWidth', {
+    writable: true,
+    configurable: true,
+    value: 1024
+  });
+  Object.defineProperty(document.documentElement, 'clientHeight', {
+    writable: true,
+    configurable: true,
+    value: 768
+  });
 });
 
 afterEach(() => {
   delete window.IntersectionObserver;
+  // Clean up the clientWidth/clientHeight properties
+  delete document.documentElement.clientWidth;
+  delete document.documentElement.clientHeight;
 });