diff --git a/flit_core/flit_core/config.py b/flit_core/flit_core/config.py
index e8e18c50..e1e55b91 100644
--- a/flit_core/flit_core/config.py
+++ b/flit_core/flit_core/config.py
@@ -65,7 +65,7 @@ class ConfigError(ValueError):
 
 
 default_license_files_globs = ['COPYING*', 'LICEN[CS]E*', 'NOTICE*', 'AUTHORS*']
-license_files_allowed_chars = re.compile(r'^[\w\-\.\/\*\?\[\]]+$')
+license_files_allowed_chars = re.compile(r'^[\w\-\.\/\*\?\[\] ]+$')
 
 
 def read_flit_config(path):
diff --git a/flit_core/tests_core/samples/pep621_license_files/Third-Party Notices.md b/flit_core/tests_core/samples/pep621_license_files/Third-Party Notices.md
new file mode 100644
index 00000000..e69de29b
diff --git a/flit_core/tests_core/test_config.py b/flit_core/tests_core/test_config.py
index eaf6dd3a..5270696c 100644
--- a/flit_core/tests_core/test_config.py
+++ b/flit_core/tests_core/test_config.py
@@ -380,6 +380,8 @@ def test_license_expr_error_unsupported_with(invalid_expr: str):
     ({'license-files': ["**/LICENSE*"]}, ["LICENSE", "module/vendor/LICENSE_VENDOR"]),
     ({'license-files': ["module/vendor/LICENSE*"]}, ["module/vendor/LICENSE_VENDOR"]),
     ({'license-files': ["LICENSE", "module/**/LICENSE*"]}, ["LICENSE", "module/vendor/LICENSE_VENDOR"]),
+    # It was decided the banning spaces was an oversight
+    ({'license-files': ["Third-Party Notices.md"]}, ["Third-Party Notices.md"]),
     # Add project.license.file + match default patterns
     ({'license': {'file': 'module/vendor/LICENSE_VENDOR'}}, ["LICENSE", "module/vendor/LICENSE_VENDOR"]),
 ])