diff --git a/src/clone-node.ts b/src/clone-node.ts
index 37bf0fc..cd08ec1 100644
--- a/src/clone-node.ts
+++ b/src/clone-node.ts
@@ -100,6 +100,7 @@ export async function cloneNode<T extends Node>(
     cloneStyle.getPropertyValue('font-family')
       .split(',')
       .filter(Boolean)
+      .map(val => val.toLowerCase())
       .forEach(val => fontFamilies.add(val))
 
     copyPseudoContent(node, clone, ownerWindow)
diff --git a/src/embed-web-font.ts b/src/embed-web-font.ts
index e7487a3..e89f51a 100644
--- a/src/embed-web-font.ts
+++ b/src/embed-web-font.ts
@@ -81,6 +81,7 @@ export async function embedWebFont<T extends Element>(
         && cssRule.style.getPropertyValue('font-family')
           .split(',')
           .filter(Boolean)
+          .map(val => val.toLowerCase())
           .some(val => fontFamilies.has(val))
       ))
       .forEach((value) => {