diff --git a/packages/popper/src/utils/getOuterSizes.js b/packages/popper/src/utils/getOuterSizes.js
index e5e60213b6..6a266b5072 100644
--- a/packages/popper/src/utils/getOuterSizes.js
+++ b/packages/popper/src/utils/getOuterSizes.js
@@ -6,7 +6,8 @@
  * @returns {Object} object containing width and height properties
  */
 export default function getOuterSizes(element) {
-  const styles = getComputedStyle(element);
+  const window = element.ownerDocument.defaultView;
+  const styles = window.getComputedStyle(element);
   const x = parseFloat(styles.marginTop) + parseFloat(styles.marginBottom);
   const y = parseFloat(styles.marginLeft) + parseFloat(styles.marginRight);
   const result = {
diff --git a/packages/popper/src/utils/getStyleComputedProperty.js b/packages/popper/src/utils/getStyleComputedProperty.js
index e2b245793c..014f32bb8e 100644
--- a/packages/popper/src/utils/getStyleComputedProperty.js
+++ b/packages/popper/src/utils/getStyleComputedProperty.js
@@ -10,6 +10,7 @@ export default function getStyleComputedProperty(element, property) {
     return [];
   }
   // NOTE: 1 DOM access here
-  const css = getComputedStyle(element, null);
+  const window = element.ownerDocument.defaultView;
+  const css = window.getComputedStyle(element, null);
   return property ? css[property] : css;
 }