diff --git a/UNRELEASED.md b/UNRELEASED.md
index d4c8cbf9183..6f69d2feb8b 100644
--- a/UNRELEASED.md
+++ b/UNRELEASED.md
@@ -10,6 +10,8 @@
 
 ### Bug fixes
 
+- Added an outline on `Banner` for Windows high contrast mode ([#2878](https://github.com/Shopify/polaris-react/pull/2878))
+
 ### Documentation
 
 ### Development workflow
diff --git a/src/components/Banner/Banner.scss b/src/components/Banner/Banner.scss
index f2af8ab9c02..600b3af5151 100644
--- a/src/components/Banner/Banner.scss
+++ b/src/components/Banner/Banner.scss
@@ -14,9 +14,7 @@ $secondary-action-horizontal-padding: 1.5 * spacing(tight);
   box-shadow: var(--p-banner-border, none);
 
   @media (-ms-high-contrast: active) {
-    box-shadow: inset 0 $accent-height 0 0 ms-high-contrast-color('text'),
-      inset 0 0 border-width(base) border-width(base)
-        ms-high-contrast-color('text');
+    outline: 1px solid;
   }
 
   @if $in-page {