diff --git a/crossplane/function/response.py b/crossplane/function/response.py
index c7b5b1d..d886725 100644
--- a/crossplane/function/response.py
+++ b/crossplane/function/response.py
@@ -163,13 +163,16 @@ def require_resources(  # noqa: PLR0913
         namespace: The namespace to search in (optional).
 
     Raises:
-        ValueError: If both match_name and match_labels are provided, or neither.
+        ValueError: If both match_name and match_labels are provided.
 
     This tells Crossplane to fetch the specified resources and include them
     in the next call to the function in req.required_resources[name].
+
+    If neither match_name nor match_labels is provided, all resources of the
+    given api_version and kind are matched.
     """
-    if (match_name is None) == (match_labels is None):
-        msg = "Exactly one of match_name or match_labels must be provided"
+    if match_name is not None and match_labels is not None:
+        msg = "match_name and match_labels are mutually exclusive"
         raise ValueError(msg)
 
     selector = fnv1.ResourceSelector(
diff --git a/tests/test_response.py b/tests/test_response.py
index fd95089..fa8edc9 100644
--- a/tests/test_response.py
+++ b/tests/test_response.py
@@ -233,6 +233,21 @@ class TestCase:
                     match_name="worker-1",
                 ),
             ),
+            TestCase(
+                reason="Should match all resources of a kind with no match field.",
+                rsp=fnv1.RunFunctionResponse(),
+                name="all-pods",
+                api_version="v1",
+                kind="Pod",
+                match_name=None,
+                match_labels=None,
+                namespace="default",
+                want_selector=fnv1.ResourceSelector(
+                    api_version="v1",
+                    kind="Pod",
+                    namespace="default",
+                ),
+            ),
         ]
 
         for case in cases:
@@ -270,17 +285,6 @@ def test_require_resources_invalid_args(self) -> None:
                 match_labels={"app": "test"},
             )
 
-        # Should raise ValueError if neither match_name nor match_labels are provided
-        with self.assertRaises(ValueError):
-            response.require_resources(
-                rsp,
-                "test",
-                "v1",
-                "Pod",
-                match_name=None,
-                match_labels=None,
-            )
-
     def test_require_schema(self) -> None:
         @dataclasses.dataclass
         class TestCase: