diff --git a/lib/rules/property-no-unknown/README.md b/lib/rules/property-no-unknown/README.md
index 61a30ee911..f5f82d4e40 100644
--- a/lib/rules/property-no-unknown/README.md
+++ b/lib/rules/property-no-unknown/README.md
@@ -127,6 +127,27 @@ The following patterns are _not_ considered violations:
 }
 ```
 
+### `ignoreAtRules: ["/regex/", /regex/, "string"]`
+
+Ignores properties nested within specified at-rules.
+
+Given:
+
+```
+["supports"]
+```
+
+The following patterns are _not_ considered violations:
+
+<!-- prettier-ignore -->
+```css
+@supports (display: grid) {
+  a {
+    my-property: 1;
+  }
+}
+```
+
 ### `checkPrefixed: true | false` (default: `false`)
 
 If `true`, this rule will check vendor-prefixed properties.
diff --git a/lib/rules/property-no-unknown/__tests__/index.js b/lib/rules/property-no-unknown/__tests__/index.js
index 2861598661..9e901babe5 100644
--- a/lib/rules/property-no-unknown/__tests__/index.js
+++ b/lib/rules/property-no-unknown/__tests__/index.js
@@ -360,3 +360,53 @@ testRule({
 		},
 	],
 });
+
+testRule({
+	ruleName,
+	config: [true, { ignoreAtRules: ['supports', /^my-/] }],
+
+	accept: [
+		{
+			code: '@supports (display: grid) { my-property: 1; }',
+		},
+		{
+			code: '@my-at-rule { foo: 1; }',
+		},
+		{
+			code: '@supports (display:grid) { @media (min-width: 10px) { foo: 1; } }',
+		},
+		{
+			code: '@supports (display:grid) { @media (min-width: 10px) { a { foo: 1; } } }',
+		},
+		{
+			code: '@my-other-at-rule { a { foo: 1; } }',
+		},
+	],
+
+	reject: [
+		{
+			code: '@media screen { a { foo: 1; } }',
+			message: messages.rejected('foo'),
+			line: 1,
+			column: 21,
+		},
+		{
+			code: '@not-my-at-rule { foo: 1; }',
+			message: messages.rejected('foo'),
+			line: 1,
+			column: 19,
+		},
+		{
+			code: 'a { foo: 1; }',
+			message: messages.rejected('foo'),
+			line: 1,
+			column: 5,
+		},
+		{
+			code: '@not-my-at-rule foobar { foo: 1; }',
+			message: messages.rejected('foo'),
+			line: 1,
+			column: 26,
+		},
+	],
+});
diff --git a/lib/rules/property-no-unknown/index.js b/lib/rules/property-no-unknown/index.js
index ec9045042c..26a914b301 100644
--- a/lib/rules/property-no-unknown/index.js
+++ b/lib/rules/property-no-unknown/index.js
@@ -33,6 +33,7 @@ function rule(actual, options) {
 					ignoreProperties: [_.isString, _.isRegExp],
 					checkPrefixed: _.isBoolean,
 					ignoreSelectors: [_.isString, _.isRegExp],
+					ignoreAtRules: [_.isString, _.isRegExp],
 				},
 				optional: true,
 			},
@@ -44,7 +45,9 @@ function rule(actual, options) {
 
 		const shouldCheckPrefixed = _.get(options, 'checkPrefixed');
 
-		root.walkDecls((decl) => {
+		root.walkDecls(checkStatement);
+
+		function checkStatement(decl) {
 			const prop = decl.prop;
 
 			if (!isStandardSyntaxProperty(prop)) {
@@ -73,6 +76,18 @@ function rule(actual, options) {
 				return;
 			}
 
+			let node = decl.parent;
+
+			while (node && node.type !== 'root') {
+				const { type, name } = node;
+
+				if (type === 'atrule' && optionsMatches(options, 'ignoreAtRules', name)) {
+					return;
+				}
+
+				node = node.parent;
+			}
+
 			if (allValidProperties.has(prop.toLowerCase())) {
 				return;
 			}
@@ -83,7 +98,7 @@ function rule(actual, options) {
 				result,
 				ruleName,
 			});
-		});
+		}
 	};
 }