diff --git a/array_api_compat/common/_helpers.py b/array_api_compat/common/_helpers.py
index e6adc948..29886ca7 100644
--- a/array_api_compat/common/_helpers.py
+++ b/array_api_compat/common/_helpers.py
@@ -53,7 +53,7 @@ def _check_api_version(api_version):
     if api_version is not None and api_version != '2021.12':
         raise ValueError("Only the 2021.12 version of the array API specification is currently supported")
 
-def array_namespace(*xs, api_version=None, _use_compat=True):
+def array_namespace(*xs, api_version=None, _use_compat=True, fallback_namespace=None):
     """
     Get the array API compatible namespace for the arrays `xs`.
 
@@ -69,10 +69,23 @@ def your_function(x, y):
     api_version should be the newest version of the spec that you need support
     for (currently the compat library wrapped APIs only support v2021.12).
     """
+    # convert fallback_namespace
+    if fallback_namespace is not None:
+        try:
+            x_ = fallback_namespace.asarray(1)
+            fallback_namespace = array_namespace(
+                x_, _use_compat=_use_compat
+            )
+        except AttributeError as exc:
+            msg = "'fallback_namespace' must be an Array API compatible namespace"
+            raise TypeError(msg) from exc
+
     namespaces = set()
     for x in xs:
         if isinstance(x, (tuple, list)):
-            namespaces.add(array_namespace(*x, _use_compat=_use_compat))
+            namespaces.add(array_namespace(
+                *x, _use_compat=_use_compat, fallback_namespace=fallback_namespace
+            ))
         elif hasattr(x, '__array_namespace__'):
             namespaces.add(x.__array_namespace__(api_version=api_version))
         elif _is_numpy_array(x):
@@ -99,6 +112,8 @@ def your_function(x, y):
             else:
                 import torch
                 namespaces.add(torch)
+        elif fallback_namespace is not None:
+            namespaces.add(fallback_namespace)
         else:
             # TODO: Support Python scalars?
             raise TypeError("The input is not a supported array type")
diff --git a/tests/test_array_namespace.py b/tests/test_array_namespace.py
index 806b1192..059d4e8e 100644
--- a/tests/test_array_namespace.py
+++ b/tests/test_array_namespace.py
@@ -26,6 +26,32 @@ def test_array_namespace_multiple():
     assert array_namespace(x, x) == array_namespace((x, x)) == \
         array_namespace((x, x), x) == array_api_compat.numpy
 
+def test_fallback_namespace():
+    import numpy as np
+    import numpy.array_api
+    import array_api_compat.numpy
+
+    xp = array_api_compat.numpy
+    xp_ = array_namespace([1, 2], fallback_namespace=xp)
+    assert xp_ == xp
+
+    xp_ = array_namespace([1, 2], np.asarray([1, 2]), fallback_namespace=xp)
+    assert xp_ == xp
+
+    # convert to Array API compatible namespace
+    xp = array_api_compat.numpy
+    xp_ = array_namespace([1, 2], np.asarray([1, 2]), fallback_namespace=np)
+    assert xp_ == xp
+
+    msg = 'Multiple namespaces'
+    with pytest.raises(TypeError, match=msg):
+        array_namespace([1, 2], numpy.array_api.asarray([1, 2]), fallback_namespace=np)
+
+    msg = "'fallback_namespace' must be an Array API"
+    with pytest.raises(TypeError, match=msg):
+        array_namespace([1, 2], np.asarray([1, 2]), fallback_namespace="hop")
+
+
 def test_array_namespace_errors():
     pytest.raises(TypeError, lambda: array_namespace([1]))
     pytest.raises(TypeError, lambda: array_namespace())