diff --git a/testing/web-platform/tests/css/css-fonts/font-size-adjust-012-ref.html b/testing/web-platform/tests/css/css-fonts/font-size-adjust-012-ref.html
index 9b24c758b625..e60769737dad 100644
--- a/testing/web-platform/tests/css/css-fonts/font-size-adjust-012-ref.html
+++ b/testing/web-platform/tests/css/css-fonts/font-size-adjust-012-ref.html
@@ -19,9 +19,9 @@
         }
         .test {
             font-family: var(--primary-font), var(--secondary-font);
-            font-size: 50px;
+            font-size: 100px;
             color: peru;
-            height: 50px;
+            height: 200px;
         }
         .primary-font {
             font-family: var(--primary-font);
diff --git a/testing/web-platform/tests/css/css-fonts/font-size-adjust-012.html b/testing/web-platform/tests/css/css-fonts/font-size-adjust-012.html
index a6037ffbacee..426349542760 100644
--- a/testing/web-platform/tests/css/css-fonts/font-size-adjust-012.html
+++ b/testing/web-platform/tests/css/css-fonts/font-size-adjust-012.html
@@ -23,9 +23,9 @@
         }
         .test {
             font-family: var(--primary-font), var(--secondary-font);
-            font-size: 50px;
+            font-size: 100px;
             color: peru;
-            height: 50px;
+            height: 200px;
         }
         .primary-font {
             font-family: var(--primary-font);
@@ -70,4 +70,4 @@
         <span class="adjusted">xA<span class="tall-inline-block"></span></span>
         </div>
     </div>
-</html>
\ No newline at end of file
+</html>
diff --git a/testing/web-platform/tests/css/css-fonts/font-size-adjust-metrics-override-ref.html b/testing/web-platform/tests/css/css-fonts/font-size-adjust-metrics-override-ref.html
new file mode 100644
index 000000000000..a8d06c9674bb
--- /dev/null
+++ b/testing/web-platform/tests/css/css-fonts/font-size-adjust-metrics-override-ref.html
@@ -0,0 +1,58 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<link rel="help" href="https://www.w3.org/TR/css-fonts-5/#font-size-adjust-prop">
+<meta name="assert" content="Tests the simultaneous use of font-size-adjust and metrics override descriptorof of @font-face">
+<title>Tests if font metric overrides reflect the adjustment of font-size-adjust.</title>
+<style>
+@font-face {
+  font-family: Ahem;
+  src: local(Ahem), url(/fonts/Ahem.ttf);
+}
+
+.reference {
+  font: 20px Ahem;
+  position: absolute;
+  top: 10px;
+  left: 10px;
+}
+
+.overridden-ascent-ref {
+  display: inline-block;
+  background-color: green;
+  width: 1em;
+  height: 1em; /* Scale a reference block to match the overridden ascent of 100%. */
+}
+
+.character {
+  display: inline-block;
+  background-color: green;
+  width: 2em;  /* Double-size of an 'X' in Ahem */
+  height: 2em; /* Double-size of an 'X' in Ahem */
+  position: absolute;
+  /* Two times of difference between the overridden ascent and the original ascent */
+  top: 0.4em;
+  left: 1em;
+}
+
+.overridden-descent-ref {
+  display: inline-block;
+  background-color: green;
+  width: 1em;
+  height: 0.5em; /* Scale a reference block to match the overridden descen of 50%. */
+  position: absolute;
+  top: 2.5em;
+  left: 3em;
+}
+
+</style>
+<!--
+The three green rectangles below show ascent, character, and descent sizes
+from the left. The ascent and descent are overridden by 100% and 50% of the
+specified font size, respectively. The test applies font-size-adjust and font
+metric overrides simultaneously to text. As we double the text size with
+font-size-adjust, the ascent and descent override should scale accordingly
+to double their size.
+-->
+<div class="reference">
+  <span class="overridden-ascent-ref"></span><span class="character"></span><span class="overridden-descent-ref"></span>
+</div>
diff --git a/testing/web-platform/tests/css/css-fonts/font-size-adjust-metrics-override.html b/testing/web-platform/tests/css/css-fonts/font-size-adjust-metrics-override.html
new file mode 100644
index 000000000000..b7787b93073a
--- /dev/null
+++ b/testing/web-platform/tests/css/css-fonts/font-size-adjust-metrics-override.html
@@ -0,0 +1,55 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<link rel="author" href="mailto:changseok@webkit.org">
+<link rel="match" href="font-size-adjust-metrics-override-ref.html">
+<link rel="help" href="https://www.w3.org/TR/css-fonts-5/#font-size-adjust-prop">
+<meta name="assert" content="Tests the simultaneous use of font-size-adjust and metrics override descriptors of @font-face">
+<title>Tests if font metric overrides reflect the adjustment of font-size-adjust.</title>
+<style>
+@font-face {
+  font-family: Ahem;
+  src: local(Ahem), url(/fonts/Ahem.ttf);
+  /* The default ascent and descent are 80% and 20%, respectively. */
+  ascent-override: 100%;
+  descent-override: 50%;
+}
+
+.size-adjusted {
+  font: 20px Ahem;
+  /* Scale up 200% since the Ahem font has an aspect ratio of 0.8 of x-height
+     to size. */
+  font-size-adjust: 1.6;
+  color: green;
+  position: absolute;
+  top: 10px;
+  left: 10px;
+}
+
+.overridden-ascent-ref {
+  display: inline-block;
+  background-color: green;
+  vertical-align: top;
+  width: 1em;
+  height: 1em; /* Scale a reference block to match the overridden ascent of 100%. */
+}
+
+.overridden-descent-ref {
+  display: inline-block;
+  background-color: green;
+  vertical-align: bottom;
+  width: 1em;
+  height: 0.5em; /* Scale a reference block to match the overridden descen of 50%. */
+}
+
+</style>
+<!--
+The three green rectangles below show ascent, character, and descent sizes
+from the left. The ascent and descent are overridden by 100% and 50% of the
+specified font size, respectively. The test applies font-size-adjust and font
+metric overrides simultaneously to text. As we double the text size with
+font-size-adjust, the ascent and descent override should scale accordingly
+to double their size.
+-->
+<div class="size-adjusted">
+  <span class="overridden-ascent-ref"></span>X<span class="overridden-descent-ref"></span>
+</div>
diff --git a/testing/web-platform/tests/lint.ignore b/testing/web-platform/tests/lint.ignore
index 95354d71e057..d7b97d233336 100644
--- a/testing/web-platform/tests/lint.ignore
+++ b/testing/web-platform/tests/lint.ignore
@@ -610,6 +610,8 @@ AHEM SYSTEM FONT: css/css-fonts/font-size-adjust-012.html
 AHEM SYSTEM FONT: css/css-fonts/font-size-adjust-012-ref.html
 AHEM SYSTEM FONT: css/css-fonts/font-size-adjust-013.html
 AHEM SYSTEM FONT: css/css-fonts/font-size-adjust-013-ref.html
+AHEM SYSTEM FONT: css/css-fonts/font-size-adjust-metrics-override.html
+AHEM SYSTEM FONT: css/css-fonts/font-size-adjust-metrics-override-ref.html
 AHEM SYSTEM FONT: css/css-fonts/line-gap-override.html
 AHEM SYSTEM FONT: html/dom/render-blocking/remove-attr-unblocks-rendering.optional.html
 AHEM SYSTEM FONT: html/dom/render-blocking/remove-element-unblocks-rendering.optional.html
