diff --git a/src/blueapi/core/context.py b/src/blueapi/core/context.py
index 9bf29aec3..26f065b6d 100644
--- a/src/blueapi/core/context.py
+++ b/src/blueapi/core/context.py
@@ -44,6 +44,7 @@
 
 from .bluesky_types import (
     BLUESKY_PROTOCOLS,
+    AsyncDevice,
     Device,
     Plan,
     PlanGenerator,
@@ -102,8 +103,12 @@ def qualified_generic_name(target: type) -> str:
     return f"{qualified_name(target)}{subscript}"
 
 
-def is_bluesky_type(typ: type) -> bool:
-    return typ in BLUESKY_PROTOCOLS or isinstance(typ, BLUESKY_PROTOCOLS)
+def is_bluesky_type(typ: Any) -> bool:
+    return (
+        typ in BLUESKY_PROTOCOLS
+        or isinstance(typ, BLUESKY_PROTOCOLS)
+        or (isinstance(typ, type) and issubclass(typ, AsyncDevice))
+    )
 
 
 C = TypeVar("C", covariant=True)
@@ -531,7 +536,7 @@ def _convert_type(self, typ: type | Any, no_default: bool = True) -> type:
         if typ is NoneType and not no_default:
             return SkipJsonSchema[NoneType]
         root = get_origin(typ)
-        if is_bluesky_type(typ) or (root is not None and is_bluesky_type(root)):
+        if is_bluesky_type(root or typ):
             return self._reference(typ)
         args = get_args(typ)
         if args:
diff --git a/tests/unit_tests/core/test_context.py b/tests/unit_tests/core/test_context.py
index 2f31784aa..9cca6fe46 100644
--- a/tests/unit_tests/core/test_context.py
+++ b/tests/unit_tests/core/test_context.py
@@ -18,8 +18,8 @@
 from bluesky.run_engine import RunEngine
 from bluesky.utils import MsgGenerator
 from dodal.common import PlanGenerator, inject
-from ophyd import Device
 from ophyd_async.core import (
+    Device,
     PathProvider,
     StandardDetector,
     StaticPathProvider,
@@ -550,6 +550,20 @@ def demo(named: ConcreteStoppable): ...
     assert spec["named"][1].default_factory is None
 
 
+class PlainDevice(Device):
+    """Class that extends Device without any additional protocols"""
+
+
+def test_device_without_protocol_annotation(empty_context: BlueskyContext):
+    dev_ref = empty_context._reference(PlainDevice)
+
+    def demo_plan(dev: PlainDevice) -> MsgGenerator:
+        yield from []
+
+    spec = empty_context._type_spec_for_function(demo_plan)
+    assert spec["dev"][0] is dev_ref
+
+
 def test_str_default(empty_context: BlueskyContext, sim_motor: Motor, alt_motor: Motor):
     movable_ref = empty_context._reference(Movable)
     empty_context.register_device(sim_motor)