diff --git a/homeassistant/helpers/singleton.py b/homeassistant/helpers/singleton.py
index 82b666be40a..ab4d12dc1cc 100644
--- a/homeassistant/helpers/singleton.py
+++ b/homeassistant/helpers/singleton.py
@@ -1,14 +1,14 @@
 """Helper to help coordinating calls."""
 import asyncio
 import functools
-from typing import Awaitable, Callable, TypeVar, cast
+from typing import Callable, Optional, TypeVar, cast
 
 from homeassistant.core import HomeAssistant
 from homeassistant.loader import bind_hass
 
 T = TypeVar("T")
 
-FUNC = Callable[[HomeAssistant], Awaitable[T]]
+FUNC = Callable[[HomeAssistant], T]
 
 
 def singleton(data_key: str) -> Callable[[FUNC], FUNC]:
@@ -19,10 +19,21 @@ def singleton(data_key: str) -> Callable[[FUNC], FUNC]:
 
     def wrapper(func: FUNC) -> FUNC:
         """Wrap a function with caching logic."""
+        if not asyncio.iscoroutinefunction(func):
+
+            @bind_hass
+            @functools.wraps(func)
+            def wrapped(hass: HomeAssistant) -> T:
+                obj: Optional[T] = hass.data.get(data_key)
+                if obj is None:
+                    obj = hass.data[data_key] = func(hass)
+                return obj
+
+            return wrapped
 
         @bind_hass
         @functools.wraps(func)
-        async def wrapped(hass: HomeAssistant) -> T:
+        async def async_wrapped(hass: HomeAssistant) -> T:
             obj_or_evt = hass.data.get(data_key)
 
             if not obj_or_evt:
@@ -41,6 +52,6 @@ def singleton(data_key: str) -> Callable[[FUNC], FUNC]:
 
             return cast(T, obj_or_evt)
 
-        return wrapped
+        return async_wrapped
 
     return wrapper
diff --git a/tests/helpers/test_singleton.py b/tests/helpers/test_singleton.py
new file mode 100644
index 00000000000..03230a02ab8
--- /dev/null
+++ b/tests/helpers/test_singleton.py
@@ -0,0 +1,40 @@
+"""Test singleton helper."""
+import pytest
+
+from homeassistant.helpers import singleton
+
+from tests.async_mock import Mock
+
+
+@pytest.fixture
+def mock_hass():
+    """Mock hass fixture."""
+    return Mock(data={})
+
+
+async def test_singleton_async(mock_hass):
+    """Test singleton with async function."""
+
+    @singleton.singleton("test_key")
+    async def something(hass):
+        return object()
+
+    result1 = await something(mock_hass)
+    result2 = await something(mock_hass)
+    assert result1 is result2
+    assert "test_key" in mock_hass.data
+    assert mock_hass.data["test_key"] is result1
+
+
+def test_singleton(mock_hass):
+    """Test singleton with function."""
+
+    @singleton.singleton("test_key")
+    def something(hass):
+        return object()
+
+    result1 = something(mock_hass)
+    result2 = something(mock_hass)
+    assert result1 is result2
+    assert "test_key" in mock_hass.data
+    assert mock_hass.data["test_key"] is result1