diff --git a/stdlib/sys.pyi b/stdlib/sys.pyi
index 313ea5877c6e..ca049124053a 100644
--- a/stdlib/sys.pyi
+++ b/stdlib/sys.pyi
@@ -359,3 +359,13 @@ if sys.version_info < (3, 8):
 # as part of the response to CVE-2020-10735
 def set_int_max_str_digits(maxdigits: int) -> None: ...
 def get_int_max_str_digits() -> int: ...
+
+if sys.version_info >= (3, 12):
+    def getunicodeinternedsize() -> int: ...
+    def deactivate_stack_trampoline() -> None: ...
+    def is_stack_trampoline_active() -> bool: ...
+    # It always exists, but raises on non-linux platforms:
+    if sys.platform == "linux":
+        def activate_stack_trampoline(__backend: str) -> None: ...
+    else:
+        def activate_stack_trampoline(__backend: str) -> NoReturn: ...
diff --git a/tests/stubtest_allowlists/py312.txt b/tests/stubtest_allowlists/py312.txt
index 3e14f8b9233c..ed209d1d447e 100644
--- a/tests/stubtest_allowlists/py312.txt
+++ b/tests/stubtest_allowlists/py312.txt
@@ -185,10 +185,6 @@ ssl.OP_LEGACY_SERVER_CONNECT
 ssl.Options.OP_LEGACY_SERVER_CONNECT
 ssl.RAND_pseudo_bytes
 ssl.wrap_socket
-sys.activate_stack_trampoline
-sys.deactivate_stack_trampoline
-sys.getunicodeinternedsize
-sys.is_stack_trampoline_active
 tarfile.AbsoluteLinkError
 tarfile.AbsolutePathError
 tarfile.FilterError