diff --git a/layout/style/res/html.css b/layout/style/res/html.css
index 204011cd1177a..b38b67ee74318 100644
--- a/layout/style/res/html.css
+++ b/layout/style/res/html.css
@@ -839,6 +839,7 @@ dialog:-moz-modal-dialog {
   -moz-top-layer: top !important;
   position: fixed;
   overflow: auto;
+  visibility: visible;
   inset-block-start: 0;
   inset-block-end: 0;
   max-width: calc(100% - 6px - 2em);
diff --git a/testing/web-platform/meta/html/semantics/interactive-elements/the-dialog-element/modal-dialog-in-visibility-hidden.html.ini b/testing/web-platform/meta/html/semantics/interactive-elements/the-dialog-element/modal-dialog-in-visibility-hidden.html.ini
deleted file mode 100644
index b38d0f6dec869..0000000000000
--- a/testing/web-platform/meta/html/semantics/interactive-elements/the-dialog-element/modal-dialog-in-visibility-hidden.html.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[modal-dialog-in-visibility-hidden.html]
-  [Modal dialog should have visibility: visible by default in UA sheet]
-    expected: FAIL