diff --git a/tests/test_user_role.py b/tests/test_user_role.py
new file mode 100644
index 0000000..cf77957
--- /dev/null
+++ b/tests/test_user_role.py
@@ -0,0 +1,69 @@
+import pytest
+
+from uncertainty_engine_types.user_role import UserRole
+
+
+@pytest.mark.parametrize(
+    "role, expected",
+    [
+        (UserRole.MEMBER, "member"),
+        (UserRole.ADMIN, "admin"),
+    ],
+)
+def test_member_value(
+    role: UserRole,
+    expected: str,
+) -> None:
+    """Test that the value of each UserRole member is correct."""
+
+    assert role == expected
+
+
+@pytest.mark.parametrize(
+    "role",
+    [
+        UserRole.MEMBER,
+        UserRole.ADMIN,
+    ],
+)
+def test_is_str_instance(role: UserRole) -> None:
+    """Test that each UserRole member is an instance of str."""
+
+    assert isinstance(role, str)
+
+
+@pytest.mark.parametrize(
+    "value, expected",
+    [
+        ("member", UserRole.MEMBER),
+        ("admin", UserRole.ADMIN),
+    ],
+)
+def test_from_value(value: str, expected: UserRole) -> None:
+    """Test that a UserRole can be created from its value."""
+
+    assert UserRole(value) is expected
+
+
+@pytest.mark.parametrize(
+    "bad_value",
+    [
+        "su",
+        "owner",
+        "",
+        "ADMIN",
+        "Member",
+    ],
+)
+def test_invalid_value_raises(bad_value: str) -> None:
+    """Test that creating a UserRole with an invalid value raises a ValueError."""
+
+    with pytest.raises(ValueError):
+        UserRole(bad_value)
+
+
+def test_all_members() -> None:
+    """Test that all UserRole members are correctly defined."""
+
+    members = {role.value for role in UserRole}
+    assert members == {"member", "admin"}
diff --git a/uncertainty_engine_types/__init__.py b/uncertainty_engine_types/__init__.py
index fe5f42a..61e8ac4 100644
--- a/uncertainty_engine_types/__init__.py
+++ b/uncertainty_engine_types/__init__.py
@@ -53,6 +53,7 @@
 from uncertainty_engine_types.token import Token
 from uncertainty_engine_types.tool_metadata import ToolMetadata
 from uncertainty_engine_types.uncertainty_plot import UncertaintyPlot
+from uncertainty_engine_types.user_role import UserRole
 from uncertainty_engine_types.vector_store import VectorStoreConfig, VectorStoreProvider
 from uncertainty_engine_types.version import __version__
 
@@ -102,6 +103,7 @@
     "Token",
     "UserContext",
     "UncertaintyPlot",
+    "UserRole",
     "utils",
     "VectorStoreConfig",
     "VectorStoreProvider",
diff --git a/uncertainty_engine_types/user_role.py b/uncertainty_engine_types/user_role.py
new file mode 100644
index 0000000..0da6176
--- /dev/null
+++ b/uncertainty_engine_types/user_role.py
@@ -0,0 +1,8 @@
+from enum import Enum
+
+
+class UserRole(str, Enum):
+    """Defines user roles for access control."""
+
+    ADMIN = "admin"
+    MEMBER = "member"
diff --git a/uncertainty_engine_types/version.py b/uncertainty_engine_types/version.py
index 6a726d8..5963297 100644
--- a/uncertainty_engine_types/version.py
+++ b/uncertainty_engine_types/version.py
@@ -1 +1 @@
-__version__ = "0.21.0"
+__version__ = "0.22.0"