diff --git a/stdlib/3/asyncio/__init__.pyi b/stdlib/3/asyncio/__init__.pyi
index f29266d16..147c8b46d 100644
--- a/stdlib/3/asyncio/__init__.pyi
+++ b/stdlib/3/asyncio/__init__.pyi
@@ -1,57 +1,12 @@
 import sys
 from typing import Type
 
+from asyncio.base_events import BaseEventLoop as BaseEventLoop
 from asyncio.coroutines import (
     coroutine as coroutine,
     iscoroutinefunction as iscoroutinefunction,
     iscoroutine as iscoroutine,
 )
-from asyncio.protocols import (
-    BaseProtocol as BaseProtocol,
-    Protocol as Protocol,
-    DatagramProtocol as DatagramProtocol,
-    SubprocessProtocol as SubprocessProtocol,
-)
-if sys.version_info >= (3, 7):
-    from asyncio.protocols import BufferedProtocol as BufferedProtocol
-from asyncio.streams import (
-    StreamReader as StreamReader,
-    StreamWriter as StreamWriter,
-    StreamReaderProtocol as StreamReaderProtocol,
-    open_connection as open_connection,
-    start_server as start_server,
-)
-from asyncio.subprocess import (
-    create_subprocess_exec as create_subprocess_exec,
-    create_subprocess_shell as create_subprocess_shell,
-)
-from asyncio.transports import (
-    BaseTransport as BaseTransport,
-    ReadTransport as ReadTransport,
-    WriteTransport as WriteTransport,
-    Transport as Transport,
-    DatagramTransport as DatagramTransport,
-    SubprocessTransport as SubprocessTransport,
-)
-from asyncio.futures import (
-    Future as Future,
-    wrap_future as wrap_future,
-)
-from asyncio.tasks import (
-    FIRST_COMPLETED as FIRST_COMPLETED,
-    FIRST_EXCEPTION as FIRST_EXCEPTION,
-    ALL_COMPLETED as ALL_COMPLETED,
-    as_completed as as_completed,
-    ensure_future as ensure_future,
-    gather as gather,
-    run_coroutine_threadsafe as run_coroutine_threadsafe,
-    shield as shield,
-    sleep as sleep,
-    wait as wait,
-    wait_for as wait_for,
-    Task as Task,
-)
-from asyncio.base_events import BaseEventLoop as BaseEventLoop
 from asyncio.events import (
     AbstractEventLoopPolicy as AbstractEventLoopPolicy,
     AbstractEventLoop as AbstractEventLoop,
@@ -65,59 +20,11 @@ from asyncio.events import (
     new_event_loop as new_event_loop,
     get_child_watcher as get_child_watcher,
     set_child_watcher as set_child_watcher,
-)
-from asyncio.queues import (
-    Queue as Queue,
-    PriorityQueue as PriorityQueue,
-    LifoQueue as LifoQueue,
-    QueueFull as QueueFull,
-    QueueEmpty as QueueEmpty,
-)
-from asyncio.locks import (
-    Lock as Lock,
-    Event as Event,
-    Condition as Condition,
-    Semaphore as Semaphore,
-    BoundedSemaphore as BoundedSemaphore,
-)
-
-from asyncio.futures import isfuture as isfuture
-from asyncio.events import (
     _set_running_loop as _set_running_loop,
     _get_running_loop as _get_running_loop,
 )
-if sys.platform == 'win32':
-    from asyncio.windows_events import *
-else:
-    from asyncio.streams import (
-        open_unix_connection as open_unix_connection,
-        start_unix_server as start_unix_server,
-    )
-    DefaultEventLoopPolicy: Type[AbstractEventLoopPolicy]
-
 if sys.version_info >= (3, 7):
-    from asyncio.events import (
-        get_running_loop as get_running_loop,
-    )
-    from asyncio.tasks import (
-        all_tasks as all_tasks,
-        create_task as create_task,
-        current_task as current_task,
-    )
-    from asyncio.runners import (
-        run as run,
-    )
-
-if sys.platform != 'win32':
-    from .unix_events import (
-        AbstractChildWatcher as AbstractChildWatcher,
-        FastChildWatcher as FastChildWatcher,
-        SafeChildWatcher as SafeChildWatcher,
-        SelectorEventLoop as SelectorEventLoop,
-    )
-    if sys.version_info >= (3, 8):
-        from .unix_events import MultiLoopChildWatcher as MultiLoopChildWatcher, ThreadedChildWatcher as ThreadedChildWatcher
-
+    from asyncio.events import get_running_loop as get_running_loop
 if sys.version_info >= (3, 8):
     from asyncio.exceptions import (
         CancelledError as CancelledError,
@@ -141,3 +48,91 @@ else:
         IncompleteReadError as IncompleteReadError,
         LimitOverrunError as LimitOverrunError,
     )
+from asyncio.futures import (
+    Future as Future,
+    isfuture as isfuture,
+    wrap_future as wrap_future,
+)
+from asyncio.locks import (
+    Lock as Lock,
+    Event as Event,
+    Condition as Condition,
+    Semaphore as Semaphore,
+    BoundedSemaphore as BoundedSemaphore,
+)
+from asyncio.protocols import (
+    BaseProtocol as BaseProtocol,
+    Protocol as Protocol,
+    DatagramProtocol as DatagramProtocol,
+    SubprocessProtocol as SubprocessProtocol,
+)
+if sys.version_info >= (3, 7):
+    from asyncio.protocols import BufferedProtocol as BufferedProtocol
+from asyncio.queues import (
+    Queue as Queue,
+    PriorityQueue as PriorityQueue,
+    LifoQueue as LifoQueue,
+    QueueFull as QueueFull,
+    QueueEmpty as QueueEmpty,
+)
+if sys.version_info >= (3, 7):
+    from asyncio.runners import run as run
+from asyncio.streams import (
+    StreamReader as StreamReader,
+    StreamWriter as StreamWriter,
+    StreamReaderProtocol as StreamReaderProtocol,
+    open_connection as open_connection,
+    start_server as start_server,
+)
+from asyncio.subprocess import (
+    create_subprocess_exec as create_subprocess_exec,
+    create_subprocess_shell as create_subprocess_shell,
+)
+from asyncio.tasks import (
+    FIRST_COMPLETED as FIRST_COMPLETED,
+    FIRST_EXCEPTION as FIRST_EXCEPTION,
+    ALL_COMPLETED as ALL_COMPLETED,
+    as_completed as as_completed,
+    ensure_future as ensure_future,
+    gather as gather,
+    run_coroutine_threadsafe as run_coroutine_threadsafe,
+    shield as shield,
+    sleep as sleep,
+    wait as wait,
+    wait_for as wait_for,
+    Task as Task,
+)
+if sys.version_info >= (3, 7):
+    from asyncio.tasks import (
+        all_tasks as all_tasks,
+        create_task as create_task,
+        current_task as current_task,
+    )
+if sys.version_info >= (3, 9):
+    from asyncio.threads import to_thread as to_thread
+from asyncio.transports import (
+    BaseTransport as BaseTransport,
+    ReadTransport as ReadTransport,
+    WriteTransport as WriteTransport,
+    Transport as Transport,
+    DatagramTransport as DatagramTransport,
+    SubprocessTransport as SubprocessTransport,
+)
+
+DefaultEventLoopPolicy: Type[AbstractEventLoopPolicy]
+if sys.platform == 'win32':
+    from asyncio.windows_events import *
+
+if sys.platform != 'win32':
+    from asyncio.streams import (
+        open_unix_connection as open_unix_connection,
+        start_unix_server as start_unix_server,
+    )
+    from .unix_events import (
+        AbstractChildWatcher as AbstractChildWatcher,
+        FastChildWatcher as FastChildWatcher,
+        SafeChildWatcher as SafeChildWatcher,
+        SelectorEventLoop as SelectorEventLoop,
+    )
+    if sys.version_info >= (3, 8):
+        from .unix_events import MultiLoopChildWatcher as MultiLoopChildWatcher, ThreadedChildWatcher as ThreadedChildWatcher
diff --git a/stdlib/3/asyncio/threads.pyi b/stdlib/3/asyncio/threads.pyi
new file mode 100644
index 000000000..52e9a63ac
--- /dev/null
+++ b/stdlib/3/asyncio/threads.pyi
@@ -0,0 +1,7 @@
+import sys
+from typing import Any, Callable, TypeVar
+
+_T = TypeVar('_T')
+
+if sys.version_info >= (3, 9):
+    async def to_thread(__func: Callable[..., _T], *args: Any, **kwargs: Any) -> _T: ...
diff --git a/tests/stubtest_whitelists/py35.txt b/tests/stubtest_whitelists/py35.txt
index 968b98b8a..2218191b5 100644
--- a/tests/stubtest_whitelists/py35.txt
+++ b/tests/stubtest_whitelists/py35.txt
@@ -4,7 +4,7 @@ asyncio.Future._loop
 asyncio.Future._tb_logger
 asyncio.Task.__init__
 asyncio.Task._wakeup
-asyncio.exceptions
+asyncio.exceptions  # Added in Python 3.8
 asyncio.futures.Future._callbacks
 asyncio.futures.Future._exception
 asyncio.futures.Future._loop
@@ -13,6 +13,7 @@ asyncio.futures._TracebackLogger.__init__
 asyncio.runners
 asyncio.tasks.Task.__init__
 asyncio.tasks.Task._wakeup
+asyncio.threads  # Added in Python 3.9
 bdb.GENERATOR_AND_COROUTINE_FLAGS
 builtins.str.maketrans
 cmath.log
diff --git a/tests/stubtest_whitelists/py36.txt b/tests/stubtest_whitelists/py36.txt
index 7c59c628c..4e37a0741 100644
--- a/tests/stubtest_whitelists/py36.txt
+++ b/tests/stubtest_whitelists/py36.txt
@@ -1,8 +1,9 @@
 asyncio.Future.__init__
-asyncio.exceptions
+asyncio.exceptions  # Added in Python 3.8
 asyncio.futures.Future.__init__
 asyncio.futures._TracebackLogger.__init__
 asyncio.runners
+asyncio.threads  # Added in Python 3.9
 builtins.str.maketrans
 cmath.log
 codecs.StreamRecoder.seek
diff --git a/tests/stubtest_whitelists/py37.txt b/tests/stubtest_whitelists/py37.txt
index 36ca263aa..6eb951799 100644
--- a/tests/stubtest_whitelists/py37.txt
+++ b/tests/stubtest_whitelists/py37.txt
@@ -6,9 +6,10 @@ asyncio.TimerHandle.__init__
 asyncio.events.AbstractEventLoop.sock_sendfile
 asyncio.events.Handle.__init__
 asyncio.events.TimerHandle.__init__
-asyncio.exceptions
+asyncio.exceptions  # Added in Python 3.8
 asyncio.futures.Future.__init__
 asyncio.futures.Future._callbacks
+asyncio.threads  # Added in Python 3.9
 builtins.dict.get
 builtins.reversed
 builtins.str.maketrans
diff --git a/tests/stubtest_whitelists/py38.txt b/tests/stubtest_whitelists/py38.txt
index 8f9fef8e2..951b13f19 100644
--- a/tests/stubtest_whitelists/py38.txt
+++ b/tests/stubtest_whitelists/py38.txt
@@ -16,6 +16,7 @@ asyncio.events.TimerHandle.__init__
 asyncio.futures.Future.__init__
 asyncio.futures.Future._callbacks
 asyncio.proactor_events._ProactorBasePipeTransport.__del__
+asyncio.threads  # Added in Python 3.9
 builtins.compile
 builtins.dict.get
 builtins.reversed