diff --git a/Lib/test/test_tokenize.py b/Lib/test/test_tokenize.py
index 4e798d789f6..213e9b46ce3 100644
--- a/Lib/test/test_tokenize.py
+++ b/Lib/test/test_tokenize.py
@@ -745,6 +745,10 @@ class TestTokenizerAdheresToPep0263(TestCase):
         f = 'tokenize_tests-utf8-coding-cookie-and-utf8-bom-sig.txt'
         self.assertTrue(self._testFile(f))
 
+    def test_bad_coding_cookie(self):
+        self.assertRaises(SyntaxError, self._testFile, 'bad_coding.py')
+        self.assertRaises(SyntaxError, self._testFile, 'bad_coding2.py')
+
 
 class Test_Tokenize(TestCase):
 
diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index 0a53435583a..d669412db3e 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -388,7 +388,7 @@ def detect_encoding(readline):
             raise SyntaxError(msg)
 
         if bom_found:
-            if codec.name != 'utf-8':
+            if encoding != 'utf-8':
                 # This behaviour mimics the Python interpreter
                 if filename is None:
                     msg = 'encoding problem: utf-8'
diff --git a/Misc/NEWS b/Misc/NEWS
index 2d17eb3e579..d06ced87520 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -23,6 +23,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #14990: Correctly fail with SyntaxError on invalid encoding
+  declaration.
+
 - Issue #14814: ipaddress now provides more informative error messages when
   constructing instances directly (changes permitted during beta due to
   provisional API status)