diff --git a/src/wsproto/frame_protocol.py b/src/wsproto/frame_protocol.py
index 288276d..4b44d07 100644
--- a/src/wsproto/frame_protocol.py
+++ b/src/wsproto/frame_protocol.py
@@ -13,6 +13,8 @@
 from enum import IntEnum
 from typing import TYPE_CHECKING, NamedTuple
 
+from .utilities import LocalProtocolError
+
 if TYPE_CHECKING:
     from collections.abc import Generator
 
@@ -588,13 +590,14 @@ def received_frames(self) -> Generator[Frame, None, None]:
 
     def close(self, code: int | None = None, reason: str | None = None) -> bytearray:
         payload = bytearray()
-        if code is CloseReason.NO_STATUS_RCVD:
+        if code == CloseReason.NO_STATUS_RCVD:
             code = None
         if code is None and reason:
             msg = "cannot specify a reason without a code"
             raise TypeError(msg)
         if code in LOCAL_ONLY_CLOSE_REASONS:
-            code = CloseReason.NORMAL_CLOSURE
+            msg = f"cannot send a close frame with local-only code {code}"
+            raise LocalProtocolError(msg)
         if code is not None:
             payload += bytearray(struct.pack("!H", code))
             if reason is not None:
diff --git a/tests/test_connection.py b/tests/test_connection.py
index 92921dc..30a1893 100644
--- a/tests/test_connection.py
+++ b/tests/test_connection.py
@@ -90,6 +90,12 @@ def test_close_whilst_closing() -> None:
         client.send(CloseConnection(code=CloseReason.NORMAL_CLOSURE))
 
 
+def test_local_only_close_reason_rejected() -> None:
+    client = Connection(CLIENT)
+    with pytest.raises(LocalProtocolError):
+        client.send(CloseConnection(code=1006))
+
+
 def test_send_after_close() -> None:
     client = Connection(CLIENT)
     client.send(CloseConnection(code=CloseReason.NORMAL_CLOSURE))
diff --git a/tests/test_frame_protocol.py b/tests/test_frame_protocol.py
index 5443348..2c42481 100644
--- a/tests/test_frame_protocol.py
+++ b/tests/test_frame_protocol.py
@@ -10,6 +10,7 @@
 
 from wsproto import extensions as wpext
 from wsproto import frame_protocol as fp
+from wsproto.utilities import LocalProtocolError
 
 
 class TestBuffer:
@@ -1047,10 +1048,14 @@ def test_no_status_rcvd_close_reason(self) -> None:
         data = proto.close(code=fp.CloseReason.NO_STATUS_RCVD)
         assert data == b"\x88\x00"
 
-    def test_local_only_close_reason(self) -> None:
+    @pytest.mark.parametrize(
+        "code",
+        [fp.CloseReason.ABNORMAL_CLOSURE, fp.CloseReason.TLS_HANDSHAKE_FAILED],
+    )
+    def test_local_only_close_reason(self, code: fp.CloseReason) -> None:
         proto = fp.FrameProtocol(client=False, extensions=[])
-        data = proto.close(code=fp.CloseReason.ABNORMAL_CLOSURE)
-        assert data == b"\x88\x02\x03\xe8"
+        with pytest.raises(LocalProtocolError):
+            proto.close(code=code)
 
     def test_ping_without_payload(self) -> None:
         proto = fp.FrameProtocol(client=False, extensions=[])