diff --git a/lib/rules/no-duplicate-selectors/__tests__/index.js b/lib/rules/no-duplicate-selectors/__tests__/index.js
index ea916974f7..400e7b694f 100644
--- a/lib/rules/no-duplicate-selectors/__tests__/index.js
+++ b/lib/rules/no-duplicate-selectors/__tests__/index.js
@@ -73,6 +73,14 @@ testRule(rule, {
       line: 1,
       column: 1
     },
+    {
+      code: ".a, .a, .a {}",
+      message: messages.rejected(".a", 1),
+      line: 1,
+      column: 1,
+      description:
+        "duplicated selectors within one rule's selector list. 3 duplicates"
+    },
     {
       code: "a {} b {} a {}",
       description: "duplicate simple selectors with another rule between",
diff --git a/lib/rules/no-duplicate-selectors/index.js b/lib/rules/no-duplicate-selectors/index.js
index 00fee878ff..cfe51f1882 100644
--- a/lib/rules/no-duplicate-selectors/index.js
+++ b/lib/rules/no-duplicate-selectors/index.js
@@ -114,20 +114,27 @@ const rule = function(actual, options) {
         });
       }
 
+      const presentedSelectors = new Set();
+      const reportedSelectors = new Set();
+
       // Or complain if one selector list contains the same selector more than one
-      rule.selectors.forEach((selector, i) => {
-        if (
-          _.includes(
-            normalizedSelectorList.slice(0, i),
-            normalizeSelector(selector)
-          )
-        ) {
+      rule.selectors.forEach(selector => {
+        const normalized = normalizeSelector(selector);
+
+        if (presentedSelectors.has(normalized)) {
+          if (reportedSelectors.has(normalized)) {
+            return;
+          }
+
           report({
             result,
             ruleName,
             node: rule,
             message: messages.rejected(selector, selectorLine)
           });
+          reportedSelectors.add(normalized);
+        } else {
+          presentedSelectors.add(normalized);
         }
       });