diff --git a/lib/rules/length-zero-no-unit/index.js b/lib/rules/length-zero-no-unit/index.js
index d92c67df5a..b5acc33aaf 100644
--- a/lib/rules/length-zero-no-unit/index.js
+++ b/lib/rules/length-zero-no-unit/index.js
@@ -5,6 +5,7 @@ const beforeBlockString = require('../../utils/beforeBlockString');
 const blurComments = require('../../utils/blurComments');
 const hasBlock = require('../../utils/hasBlock');
 const isCustomProperty = require('../../utils/isCustomProperty');
+const isLessVariable = require('../../utils/isLessVariable');
 const isMathFunction = require('../../utils/isMathFunction');
 const keywordSets = require('../../reference/keywordSets');
 const optionsMatches = require('../../utils/optionsMatches');
@@ -66,7 +67,7 @@ const rule = function(actual, secondary, context) {
 
 		root.walkAtRules((atRule) => {
 			// Ignore Less variables
-			if (atRule.variable && !hasBlock(atRule)) {
+			if (isLessVariable(atRule)) {
 				return;
 			}
 
diff --git a/lib/utils/__tests__/isLessVariable.test.js b/lib/utils/__tests__/isLessVariable.test.js
new file mode 100644
index 0000000000..a49c83c7cc
--- /dev/null
+++ b/lib/utils/__tests__/isLessVariable.test.js
@@ -0,0 +1,46 @@
+'use strict';
+
+const isLessVariable = require('../isLessVariable');
+const less = require('postcss-less');
+
+describe('isLessVariable', () => {
+	it('is less variable', () => {
+		lessAtRules('@var: 10px;', (atRule) => {
+			expect(isLessVariable(atRule)).toBeTruthy();
+		});
+	});
+
+	it('is less variable with function', () => {
+		lessAtRules('@hover-color: darken(@color, 10%);', (atRule) => {
+			expect(isLessVariable(atRule)).toBeTruthy();
+		});
+	});
+
+	it('@charset is not a less variable', () => {
+		lessAtRules('@charset UTF-8;', (atRule) => {
+			expect(isLessVariable(atRule)).toBeFalsy();
+		});
+	});
+
+	it('@import is not a less variable', () => {
+		lessAtRules('@import url("some-styles.css");', (atRule) => {
+			expect(isLessVariable(atRule)).toBeFalsy();
+		});
+	});
+
+	it('@media is not a less variable', () => {
+		lessAtRules('@media (min-width: 100px) {};', (atRule) => {
+			expect(isLessVariable(atRule)).toBeFalsy();
+		});
+	});
+
+	it('detached ruleset is not a less variable', () => {
+		lessAtRules('@detached-ruleset: { margin: 0 };', (atRule) => {
+			expect(isLessVariable(atRule)).toBeFalsy();
+		});
+	});
+});
+
+function lessAtRules(css, cb) {
+	less.parse(css).walkAtRules(cb);
+}
diff --git a/lib/utils/isLessVariable.js b/lib/utils/isLessVariable.js
new file mode 100644
index 0000000000..e873a4266c
--- /dev/null
+++ b/lib/utils/isLessVariable.js
@@ -0,0 +1,8 @@
+/* @flow */
+'use strict';
+
+const hasBlock = require('./hasBlock');
+
+module.exports = function(atRule /*: Object*/) /*: boolean*/ {
+	return atRule.type === 'atrule' && atRule.variable && !hasBlock(atRule);
+};