diff --git a/tools/lint/lib/checks/features.py b/tools/lint/lib/checks/features.py
index fdfa57aec1..bbb7214a45 100644
--- a/tools/lint/lib/checks/features.py
+++ b/tools/lint/lib/checks/features.py
@@ -29,3 +29,6 @@ class CheckFeatures(Check):
         for feature in features:
             if feature not in self.valid_features:
                 return 'Unrecognized feature: "%s"' % feature
+
+        if len(set(features)) != len(features):
+            return 'The `features` tag may not include duplicate entries'
diff --git a/tools/lint/test/fixtures/test/features_duplicated.js b/tools/lint/test/fixtures/test/features_duplicated.js
new file mode 100644
index 0000000000..f70b7044dc
--- /dev/null
+++ b/tools/lint/test/fixtures/test/features_duplicated.js
@@ -0,0 +1,11 @@
+FEATURES
+^ expected errors | v input
+// Copyright (C) 2021 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-assignment-operators-static-semantics-early-errors
+description: Duplicated values in "features" frontmatter
+features: [object-spread, async-functions, object-spread]
+---*/
+
+async function f({ ...a }) {}