diff --git a/src/ssvc/namespaces.py b/src/ssvc/namespaces.py
index 9eecc653..128ee648 100644
--- a/src/ssvc/namespaces.py
+++ b/src/ssvc/namespaces.py
@@ -79,13 +79,21 @@ def validate(cls, value: str) -> str:
         """
         valid = NS_PATTERN.match(value)
 
+        ext_sep = "/"
+        frag_sep = "#"
+
         if valid:
             # pattern matches, so we can proceed with further checks
             # partition always returns three parts: the part before the separator, the separator itself, and the part after the separator
-            (base_ns, _, extension) = value.partition("/")
+            (base_ns, _, extension) = value.partition(ext_sep)
             # and we don't care about the extension beyond the pattern match above
             # so base_ns is either the full value or the part before the first slash
 
+            # but base_ns might have a fragment
+            # so we need to split that off if present
+            if "#" in base_ns:
+                (base_ns, _, fragment) = base_ns.partition(frag_sep)
+
             if base_ns in cls.__members__.values():
                 # base_ns is a registered namespaces
                 return value
diff --git a/src/test/test_namespaces.py b/src/test/test_namespaces.py
index d506fcaf..1469d813 100644
--- a/src/test/test_namespaces.py
+++ b/src/test/test_namespaces.py
@@ -18,7 +18,6 @@
 #  DM24-0278
 
 import unittest
-import re
 
 from ssvc.namespaces import NameSpace
 from ssvc.utils.patterns import NS_PATTERN
@@ -88,6 +87,8 @@ def test_namespace_validator(self):
             "x_example.test#bar",
             "x_example.test#baz",
             "x_example.test#quux",
+            "ssvc",
+            "ssvc#test",
         ]:
             self.assertEqual(ns, NameSpace.validate(ns))
 
diff --git a/src/test/test_namespaces_pattern.py b/src/test/test_namespaces_pattern.py
index ff7b72d2..f8a9e884 100644
--- a/src/test/test_namespaces_pattern.py
+++ b/src/test/test_namespaces_pattern.py
@@ -40,6 +40,8 @@ def setUp(self):
             "cisa",
             "custom",  # not in enum, but valid for the pattern
             "abc",  # not in enum, but valid for the pattern
+            "ssvc#reference-arch-1",  # valid namespace with hash
+            "x_example.test#test",
             "x_example.test#test/",
             "x_example.test#test//.org.example#bar",
             "ssvc/de-DE/.org.example#reference-arch-1",  # valid BCP-47 tag, reverse domain notation, hash