diff --git a/changelog/894.fixed.md b/changelog/894.fixed.md
new file mode 100644
index 00000000..ee904ade
--- /dev/null
+++ b/changelog/894.fixed.md
@@ -0,0 +1 @@
+Generate protocols where optional attributes with a default value renders attributes that are required, i.e. not nullable.
diff --git a/infrahub_sdk/protocols_generator/generator.py b/infrahub_sdk/protocols_generator/generator.py
index 38bc968f..14c8438f 100644
--- a/infrahub_sdk/protocols_generator/generator.py
+++ b/infrahub_sdk/protocols_generator/generator.py
@@ -117,7 +117,7 @@ def _jinja2_filter_syncify(value: str | list, sync: bool = False) -> str | list:
     def _jinja2_filter_render_attribute(value: AttributeSchemaAPI) -> str:
         attribute_kind: str = ATTRIBUTE_KIND_MAP[value.kind]
 
-        if value.optional:
+        if value.optional and value.default_value is None:
             attribute_kind += "Optional"
 
         return f"{value.name}: {attribute_kind}"
diff --git a/tests/unit/sdk/test_protocols_generator.py b/tests/unit/sdk/test_protocols_generator.py
index 55796db6..730f962c 100644
--- a/tests/unit/sdk/test_protocols_generator.py
+++ b/tests/unit/sdk/test_protocols_generator.py
@@ -1,10 +1,11 @@
 from dataclasses import dataclass
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 import pytest
 
 from infrahub_sdk import InfrahubClient
 from infrahub_sdk.protocols_generator.generator import CodeGenerator
+from infrahub_sdk.schema import AttributeSchemaAPI
 
 if TYPE_CHECKING:
     from pytest_httpx import HTTPXMock
@@ -36,6 +37,56 @@ class SyncifyTestCase:
 ]
 
 
+@dataclass
+class RenderAttributeTestCase:
+    name: str
+    optional: bool
+    default_value: Any
+    expected: str
+
+
+RENDER_ATTRIBUTE_TEST_CASES = [
+    RenderAttributeTestCase(
+        name="required-no-default",
+        optional=False,
+        default_value=None,
+        expected="enabled: Boolean",
+    ),
+    RenderAttributeTestCase(
+        name="required-with-default",
+        optional=False,
+        default_value=True,
+        expected="enabled: Boolean",
+    ),
+    RenderAttributeTestCase(
+        name="optional-no-default",
+        optional=True,
+        default_value=None,
+        expected="enabled: BooleanOptional",
+    ),
+    RenderAttributeTestCase(
+        name="optional-with-default",
+        optional=True,
+        default_value=True,
+        expected="enabled: Boolean",
+    ),
+]
+
+
+@pytest.mark.parametrize(
+    "test_case",
+    [pytest.param(tc, id=tc.name) for tc in RENDER_ATTRIBUTE_TEST_CASES],
+)
+async def test_filter_render_attribute(test_case: RenderAttributeTestCase) -> None:
+    attr = AttributeSchemaAPI(
+        name="enabled",
+        kind="Boolean",
+        optional=test_case.optional,
+        default_value=test_case.default_value,
+    )
+    assert CodeGenerator._jinja2_filter_render_attribute(attr) == test_case.expected
+
+
 @pytest.mark.parametrize(
     "test_case",
     [pytest.param(tc, id=tc.name) for tc in SYNCIFY_TEST_CASES],