diff --git a/packages/block-editor/src/components/block-list/style.scss b/packages/block-editor/src/components/block-list/style.scss
index a0cd8651776ba4..2e150322c17623 100644
--- a/packages/block-editor/src/components/block-list/style.scss
+++ b/packages/block-editor/src/components/block-list/style.scss
@@ -172,6 +172,7 @@
 			// 2px outside.
 			box-shadow: 0 0 0 var(--wp-admin-border-width-focus) var(--wp-admin-theme-color);
 			border-radius: $radius-block-ui - $border-width; // Border is outset, so subtract the width to achieve correct radius.
+			outline: 2px solid transparent; // This shows up in Windows High Contrast Mode.
 
 			// Show a light color for dark themes.
 			.is-dark-theme & {