diff --git a/metadata/fields/custom/license.py b/metadata/fields/custom/license.py
index bd3e2d131..bf1e161fd 100644
--- a/metadata/fields/custom/license.py
+++ b/metadata/fields/custom/license.py
@@ -18,7 +18,7 @@ sys.path.insert(0, _ROOT_DIR)
 import metadata.fields.field_types as field_types
 import metadata.fields.util as util
 import metadata.validation_result as vr
-from metadata.fields.custom.license_allowlist import ALLOWED_SPDX_LICENSES
+from metadata.fields.custom.license_allowlist import ALLOWED_LICENSES
 
 
 def process_license_value(value: str,
@@ -57,7 +57,7 @@ def is_license_allowlisted(value: str) -> bool:
     """Returns whether the value is in the allowlist for license
     types.
     """
-    return value in ALLOWED_SPDX_LICENSES
+    return value in ALLOWED_LICENSES
 
 
 class LicenseField(field_types.SingleLineTextField):
diff --git a/metadata/fields/custom/license_allowlist.py b/metadata/fields/custom/license_allowlist.py
index 0a43995ed..4fb6e1a1e 100644
--- a/metadata/fields/custom/license_allowlist.py
+++ b/metadata/fields/custom/license_allowlist.py
@@ -65,3 +65,48 @@ ALLOWED_SPDX_LICENSES = frozenset([
     "MPL-1.1",
     "MPL-2.0",
 ])
+
+# These are licenses that are not in the SPDX license list, but are identified
+# by the license classifier.
+EXTENDED_LICENSE_CLASSIFIERS = frozenset([
+    # unencumbered.
+    "AhemFont",
+    "Android-SDK",
+    "LZMA",
+    "SPL-SQRT-FLOOR",
+    "public-domain-md5",
+    # permissive.
+    "LicenseRef-AMSFonts-2.2",
+    "test_fonts",
+    # notice.
+    "Apache-with-LLVM-Exception",
+    "Apache-with-Runtime-Exception",
+    "BSD-2-Clause-Flex",
+    "BSD-3-Clause-OpenMPI",
+    "BSD-4-Clause-Wasabi",
+    "Bitstream",
+    "CERN",
+    "Caffe",
+    "Entenssa",
+    "FFT2D",
+    "GIF-Encoder",
+    "GNU-All-permissive-Copying-License",
+    "IBM-DHCP",
+    "JsonCPP",
+    "Khronos",
+    "Libpng-2.0",
+    "LicenseRef-OpenGLUT",
+    "LicenseRef-base64",
+    "LicenseRef-takuya-ooura",
+    "Punycode",
+    "SSLeay",
+    "WebM-Project-Patent",
+    "X11-Lucent",
+    "cURL",
+    "dso",
+    "getopt",
+    "pffft",
+    "zxing",
+])
+
+ALLOWED_LICENSES = ALLOWED_SPDX_LICENSES | EXTENDED_LICENSE_CLASSIFIERS