diff --git a/modules/primer-popover/lib/popover.scss b/modules/primer-popover/lib/popover.scss
index ced3ca72..f732ec7f 100644
--- a/modules/primer-popover/lib/popover.scss
+++ b/modules/primer-popover/lib/popover.scss
@@ -172,7 +172,7 @@
   }
 }
 
-.Popover-message-large {
+.Popover-message--large {
 
   @include breakpoint(sm) {
     min-width: 320px;