diff --git a/lib/rules/unit-no-unknown/__tests__/index.js b/lib/rules/unit-no-unknown/__tests__/index.js
index 41319c467c..6ddbc6c644 100644
--- a/lib/rules/unit-no-unknown/__tests__/index.js
+++ b/lib/rules/unit-no-unknown/__tests__/index.js
@@ -437,6 +437,19 @@ testRule(rule, {
 			code: 'a { margin: calc(100% - #{$margin * 2}); }',
 			description: 'work with interpolation',
 		},
+		{
+			code: '$foo: ( 1prop: 10px, 2prop: 12px, 3prop: /* comment */ 14px )',
+			description: 'ignore map property name',
+		},
+		{
+			code: '$breakpoints: ( small: /* comment */ 767px, 1medium: 992px, large: 1200px );',
+			description: 'ignore map property name',
+		},
+		{
+			code:
+				'$breakpoints: ( small: /* comment */ 767px, medium: ( 1prop: 992px, 2prop: ( 1prop: 1200px ) ) );',
+			description: 'ignore map property name in nested maps',
+		},
 	],
 
 	reject: [
@@ -470,6 +483,19 @@ testRule(rule, {
 			line: 1,
 			column: 39,
 		},
+		{
+			code: '$breakpoints: ( small: 767px, 1medium: 992pix, large: 1200px );',
+			message: messages.rejected('pix'),
+			line: 1,
+			column: 40,
+		},
+		{
+			code:
+				'$breakpoints: ( small: /* comment */ 767px, medium: ( 1prop: 992pix, 2prop: ( 1prop: 1200px ) ) );',
+			message: messages.rejected('pix'),
+			line: 1,
+			column: 49,
+		},
 		{
 			code: 'a { font: (italic bold 10px/8pix) }',
 			message: messages.rejected('pix'),
diff --git a/lib/rules/unit-no-unknown/index.js b/lib/rules/unit-no-unknown/index.js
index 763257bf33..c6ad74c292 100644
--- a/lib/rules/unit-no-unknown/index.js
+++ b/lib/rules/unit-no-unknown/index.js
@@ -4,6 +4,7 @@ const _ = require('lodash');
 const atRuleParamIndex = require('../../utils/atRuleParamIndex');
 const declarationValueIndex = require('../../utils/declarationValueIndex');
 const getUnitFromValueNode = require('../../utils/getUnitFromValueNode');
+const isMap = require('../../utils/isMap');
 const keywordSets = require('../../reference/keywordSets');
 const mediaParser = require('postcss-media-query-parser').default;
 const optionsMatches = require('../../utils/optionsMatches');
@@ -18,6 +19,10 @@ const messages = ruleMessages(ruleName, {
 	rejected: (unit) => `Unexpected unknown unit "${unit}"`,
 });
 
+// The map property name (in map cleared from comments and spaces) always
+// has index that being divided by 4 gives remainder equals 0
+const mapPropertyNameIndexOffset = 4;
+
 const rule = function(actual, options) {
 	return (root, result) => {
 		const validOptions = validateOptions(
@@ -43,6 +48,7 @@ const rule = function(actual, options) {
 			// by postcss-value-parser
 			value = value.replace(/\*/g, ',');
 			const parsedValue = valueParser(value);
+			const ignoredMapProperties = [];
 
 			parsedValue.walk(function(valueNode) {
 				// Ignore wrong units within `url` function
@@ -55,6 +61,18 @@ const rule = function(actual, options) {
 					return false;
 				}
 
+				if (isMap(valueNode)) {
+					valueNode.nodes.forEach((node, index) => {
+						if (!(index % mapPropertyNameIndexOffset)) {
+							ignoredMapProperties.push(node.sourceIndex);
+						}
+					});
+				}
+
+				if (ignoredMapProperties.includes(valueNode.sourceIndex)) {
+					return;
+				}
+
 				const unit = getUnitFromValueNode(valueNode);
 
 				if (!unit) {
diff --git a/lib/utils/__tests__/isMap.test.js b/lib/utils/__tests__/isMap.test.js
new file mode 100644
index 0000000000..8d03db1d4f
--- /dev/null
+++ b/lib/utils/__tests__/isMap.test.js
@@ -0,0 +1,66 @@
+'use strict';
+
+const isMap = require('../isMap');
+const sass = require('postcss-sass');
+const scss = require('postcss-scss');
+const valueParser = require('postcss-value-parser');
+
+describe('isMap', () => {
+	const simpleMaps = [
+		['$map: (prop: "flex");', true],
+		['$font: (italic bold 10px/8pix)', false],
+		['$map: (prop: /* comment */ 0);', true],
+		['$calc: calc(100% / 2px);', false],
+		['$url: url();', false],
+	];
+	const nestedMaps = [
+		['$map: (prop: 0, prop2: (prop3: "normal"), prop4: 2px);', [0, 17]],
+		['$map: (prop: 0, prop2: (prop3: "normal", prop4: (prop5: "grid")), prop6: 2px);', [0, 17, 42]],
+	];
+
+	test.each(simpleMaps)('simple maps', (css, expected) => {
+		runTests(css, (decl) => {
+			const parsedValue = valueParser(decl.value).nodes[0];
+
+			expect(isMap(parsedValue)).toBe(expected);
+		});
+	});
+
+	test.each(nestedMaps)('nested maps', (css, expected) => {
+		runTests(css, (decl) => {
+			const parsedValue = valueParser(decl.value);
+
+			parsedValue.walk(function(valueNode) {
+				if (expected.includes(valueNode.sourceIndex)) {
+					expect(isMap(valueNode)).toBeTruthy();
+				} else {
+					expect(isMap(valueNode)).toBeFalsy();
+				}
+			});
+		});
+	});
+
+	it('empty map returns `false`', () => {
+		const emptyMap = '$map: ();';
+
+		runTests(emptyMap, (decl) => {
+			const parsedValue = valueParser(decl.value);
+
+			expect(isMap(parsedValue)).toBeFalsy();
+		});
+	});
+});
+
+function sassDecls(css, cb) {
+	sass.parse(css).walkDecls(cb);
+}
+
+function scssDecls(css, cb) {
+	scss.parse(css).walkDecls(cb);
+}
+
+function runTests(css, cb) {
+	[sassDecls, scssDecls].forEach((fn) => {
+		fn(css, cb);
+	});
+}
diff --git a/lib/utils/isMap.js b/lib/utils/isMap.js
new file mode 100644
index 0000000000..57bfec546b
--- /dev/null
+++ b/lib/utils/isMap.js
@@ -0,0 +1,44 @@
+'use strict';
+
+/** @typedef {import('postcss-value-parser').Node} ValueNode */
+
+/**
+ * @param {ValueNode | undefined} valueNode
+ * @returns {boolean}
+ */
+module.exports = function(valueNode) {
+	if (!valueNode) {
+		return false;
+	}
+
+	if (valueNode.type !== 'function' || !valueNode.nodes || valueNode.value) {
+		return false;
+	}
+
+	// It's necessary to remove comments and spaces if they are present
+	const cleanNodes = valueNode.nodes.filter(
+		(node) => node.type !== 'comment' && node.type !== 'space',
+	);
+
+	// Map without comments and spaces will have the structure like $map (prop: value, prop2: value)
+	//                                                                     ↑  ↑   ↑  ↑
+	//                                                                     0  1   2  3
+	if (cleanNodes[0] && cleanNodes[0].type !== 'word' && cleanNodes[0].type !== 'string') {
+		return false;
+	}
+
+	if (cleanNodes[1] && cleanNodes[1].value !== ':') {
+		return false;
+	}
+
+	// There is no need to check type or value of this node since it could be anything
+	if (!cleanNodes[2]) {
+		return false;
+	}
+
+	if (cleanNodes[3] && cleanNodes[3].value !== ',') {
+		return false;
+	}
+
+	return true;
+};