diff --git a/lib/reference/keywordSets.js b/lib/reference/keywordSets.js
index <HASH>..<HASH> 100644
--- a/lib/reference/keywordSets.js
+++ b/lib/reference/keywordSets.js
@@ -642,6 +642,7 @@ keywordSets.atRules = uniteSets(keywordSets.pageMarginAtRules, [
 	'font-feature-values',
 	'import',
 	'keyframes',
+	'layer',
 	'media',
 	'namespace',
 	'nest',
diff --git a/lib/rules/at-rule-no-unknown/__tests__/index.js b/lib/rules/at-rule-no-unknown/__tests__/index.js
index <HASH>..<HASH> 100644
--- a/lib/rules/at-rule-no-unknown/__tests__/index.js
+++ b/lib/rules/at-rule-no-unknown/__tests__/index.js
@@ -82,6 +82,9 @@ testRule({
 		{
 			code: '.foo { color: red; @nest .parent & { color: blue; } }',
 		},
+		{
+			code: '@layer framework { h1 { background: white; } }',
+		},
 	],
 
 	reject: [
Fix `at-rule-no-unknown` false positives for `@layer` (#<I>)