diff --git a/UNRELEASED.md b/UNRELEASED.md
index 88b17528317..2326de79661 100644
--- a/UNRELEASED.md
+++ b/UNRELEASED.md
@@ -12,6 +12,8 @@ Use [the changelog guidelines](/documentation/Versioning%20and%20changelog.md) t
 
 ### Bug fixes
 
+- Centered full width `Popover` on small viewports ([#4114](https://github.com/Shopify/polaris-react/pull/4114))
+
 ### Documentation
 
 ### Development workflow
diff --git a/src/components/Popover/Popover.scss b/src/components/Popover/Popover.scss
index 36472fbf789..b139d143f0c 100644
--- a/src/components/Popover/Popover.scss
+++ b/src/components/Popover/Popover.scss
@@ -42,8 +42,7 @@ $vertical-motion-offset: rem(-5px);
 }
 
 .fullWidth {
-  margin: 0;
-  margin-top: $visible-portion-of-arrow;
+  margin: $visible-portion-of-arrow auto 0 auto;
 
   .Content {
     max-width: none;
@@ -54,7 +53,7 @@ $vertical-motion-offset: rem(-5px);
   margin: spacing() spacing(tight) $visible-portion-of-arrow;
 
   &.fullWidth {
-    margin: 0 0 $visible-portion-of-arrow;
+    margin: 0 auto $visible-portion-of-arrow auto;
   }
 }