diff --git a/permit/api/role_assignments.py b/permit/api/role_assignments.py
index 09223a9..863c675 100644
--- a/permit/api/role_assignments.py
+++ b/permit/api/role_assignments.py
@@ -1,4 +1,4 @@
-from typing import List, Optional
+from typing import List, Optional, Union
 
 from ..utils.pydantic_version import PYDANTIC_VERSION
 
@@ -44,7 +44,7 @@ def __role_assignments(self) -> SimpleHttpClient:
     async def list(
         self,
         user_key: Optional[str] = None,
-        role_key: Optional[str] = None,
+        role_key: Optional[Union[str, List[str]]] = None,
         tenant_key: Optional[str] = None,
         resource_instance_key: Optional[str] = None,
         page: int = 1,
@@ -68,15 +68,19 @@ async def list(
             PermitApiError: If the API returns an error HTTP status code.
             PermitContextError: If the configured ApiContext does not match the required endpoint context.
         """
-        params = pagination_params(page, per_page)
+        params = list(pagination_params(page, per_page).items())
         if user_key is not None:
-            params.update(dict(user=user_key))
+            params.append(("user", user_key))
         if role_key is not None:
-            params.update(dict(role=role_key))
+            if isinstance(role_key, list):
+                for role in role_key:
+                    params.append(("role", role))
+            else:
+                params.append(("role", role_key))
         if tenant_key is not None:
-            params.update(dict(tenant=tenant_key))
+            params.append(("tenant", tenant_key))
         if resource_instance_key is not None:
-            params.update(dict(resource_instance=resource_instance_key))
+            params.append(("resource_instance", resource_instance_key))
         return await self.__role_assignments.get(
             "",
             model=List[RoleAssignmentRead],
diff --git a/tests/endpoints/test_role_assignments.py b/tests/endpoints/test_role_assignments.py
new file mode 100644
index 0000000..babe8b4
--- /dev/null
+++ b/tests/endpoints/test_role_assignments.py
@@ -0,0 +1,49 @@
+from contextlib import contextmanager
+
+from permit import Permit, PermitApiError, RoleAssignmentCreate, RoleCreate, UserCreate
+
+
+@contextmanager
+def suppress_409():
+    try:
+        yield
+    except PermitApiError as e:
+        if e.status_code != 409:
+            raise e
+
+
+async def create_role_assignments(permit: Permit, role_key: str, user_count: int = 10):
+    with suppress_409():
+        await permit.api.roles.create(RoleCreate(key=role_key, name=role_key))
+    with suppress_409():
+        await permit.api.users.bulk_create(
+            [UserCreate(key=f"user-{index}") for index in range(user_count)]
+        )
+    with suppress_409():
+        await permit.api.role_assignments.bulk_assign(
+            [
+                RoleAssignmentCreate(
+                    role=role_key, user=f"user-{index}", tenant="default"
+                )
+                for index in range(user_count)
+            ]
+        )
+
+
+async def test_list_filter_by_role(permit: Permit):
+    await create_role_assignments(permit, "role-1")
+    await create_role_assignments(permit, "role-2")
+    role_assignments = await permit.api.role_assignments.list(role_key="role-1")
+    assert len(role_assignments) == 10
+    assert {ra.role for ra in role_assignments} == {"role-1"}
+
+
+async def test_list_filter_by_role_multiple(permit: Permit):
+    await create_role_assignments(permit, "role-1")
+    await create_role_assignments(permit, "role-2")
+    await create_role_assignments(permit, "role-3")
+    role_assignments = await permit.api.role_assignments.list(
+        role_key=["role-1", "role-2"]
+    )
+    assert len(role_assignments) == 20
+    assert {ra.role for ra in role_assignments} == {"role-1", "role-2"}