diff --git a/src/flake8/defaults.py b/src/flake8/defaults.py
index ec68067..1b5d091 100644
--- a/src/flake8/defaults.py
+++ b/src/flake8/defaults.py
@@ -28,12 +28,14 @@ NOQA_INLINE_REGEXP = re.compile(
     # ``# noqa``
     # ``# noqa: E123``
     # ``# noqa: E123,W451,F921``
+    # ``# noqa:E123,W451,F921``
     # ``# NoQA: E123,W451,F921``
     # ``# NOQA: E123,W451,F921``
+    # ``# NOQA: E123,W451,F921``
     # We do not want to capture the ``: `` that follows ``noqa``
     # We do not care about the casing of ``noqa``
     # We want a comma-separated list of errors
-    r"# noqa(?:: (?P<codes>([A-Z][0-9]+(?:[,\s]+)?)+))?",
+    r"# noqa(?::[\s]?(?P<codes>([A-Z][0-9]+(?:[,\s]+)?)+))?",
     re.IGNORECASE,
 )