diff --git a/Doc/c-api/arg.rst b/Doc/c-api/arg.rst
index 9713431688d499..36090aaf7d327b 100644
--- a/Doc/c-api/arg.rst
+++ b/Doc/c-api/arg.rst
@@ -70,9 +70,10 @@ There are three ways strings and buffers can be converted to C:
 
 .. note::
 
-   For all ``#`` variants of formats (``s#``, ``y#``, etc.), the macro
-   :c:macro:`PY_SSIZE_T_CLEAN` must be defined before including
-   :file:`Python.h`. On Python 3.9 and older, the type of the length argument
+   From Python 3.10 to 3.12, the macro :c:macro:`PY_SSIZE_T_CLEAN` had to
+   be defined before including :file:`Python.h` to use all ``#`` variants of
+   formats (``s#``, ``y#``, etc.).
+   On Python 3.9 and older, the type of the length argument
    is :c:type:`Py_ssize_t` if the :c:macro:`PY_SSIZE_T_CLEAN` macro is defined,
    or int otherwise.
 
diff --git a/Doc/c-api/intro.rst b/Doc/c-api/intro.rst
index 8de76e55cd0586..7d583774902fec 100644
--- a/Doc/c-api/intro.rst
+++ b/Doc/c-api/intro.rst
@@ -48,7 +48,7 @@ Include Files
 All function, type and macro definitions needed to use the Python/C API are
 included in your code by the following line::
 
-   #define PY_SSIZE_T_CLEAN
+   #define PY_SSIZE_T_CLEAN  /* needed until Python 3.12 */
    #include <Python.h>
 
 This implies inclusion of the following standard headers: ``<stdio.h>``,
diff --git a/Doc/data/stable_abi.dat b/Doc/data/stable_abi.dat
index f112d268129fd1..55b3ac88b4eca4 100644
--- a/Doc/data/stable_abi.dat
+++ b/Doc/data/stable_abi.dat
@@ -1,12 +1,7 @@
 role,name,added,ifdef_note,struct_abi_kind
 macro,PY_VECTORCALL_ARGUMENTS_OFFSET,3.12,,
 function,PyAIter_Check,3.10,,
-function,PyArg_Parse,3.2,,
-function,PyArg_ParseTuple,3.2,,
-function,PyArg_ParseTupleAndKeywords,3.2,,
 function,PyArg_UnpackTuple,3.2,,
-function,PyArg_VaParse,3.2,,
-function,PyArg_VaParseTupleAndKeywords,3.2,,
 function,PyArg_ValidateKeywordArguments,3.2,,
 var,PyBaseObject_Type,3.2,,
 function,PyBool_FromLong,3.2,,
@@ -490,9 +485,7 @@ function,PyObject_AsReadBuffer,3.2,,
 function,PyObject_AsWriteBuffer,3.2,,
 function,PyObject_Bytes,3.2,,
 function,PyObject_Call,3.2,,
-function,PyObject_CallFunction,3.2,,
 function,PyObject_CallFunctionObjArgs,3.2,,
-function,PyObject_CallMethod,3.2,,
 function,PyObject_CallMethodObjArgs,3.2,,
 function,PyObject_CallNoArgs,3.10,,
 function,PyObject_CallObject,3.2,,
@@ -808,7 +801,6 @@ function,Py_AddPendingCall,3.2,,
 function,Py_AtExit,3.2,,
 macro,Py_BEGIN_ALLOW_THREADS,3.2,,
 macro,Py_BLOCK_THREADS,3.2,,
-function,Py_BuildValue,3.2,,
 function,Py_BytesMain,3.8,,
 function,Py_CompileString,3.2,,
 function,Py_DecRef,3.2,,
@@ -860,7 +852,6 @@ function,Py_SetRecursionLimit,3.2,,
 type,Py_UCS4,3.2,,
 macro,Py_UNBLOCK_THREADS,3.2,,
 var,Py_UTF8Mode,3.8,,
-function,Py_VaBuildValue,3.2,,
 var,Py_Version,3.11,,
 function,Py_XNewRef,3.10,,
 type,Py_buffer,3.11,,full-abi
diff --git a/Doc/extending/extending.rst b/Doc/extending/extending.rst
index d9bf4fd6c7ae0e..5238f6c40aa76e 100644
--- a/Doc/extending/extending.rst
+++ b/Doc/extending/extending.rst
@@ -649,7 +649,7 @@ Note that any Python object references which are provided to the caller are
 
 Some example calls::
 
-   #define PY_SSIZE_T_CLEAN  /* Make "s#" use Py_ssize_t rather than int. */
+   #define PY_SSIZE_T_CLEAN  /* needed until Python 3.12 */
    #include <Python.h>
 
 ::
diff --git a/Doc/whatsnew/3.13.rst b/Doc/whatsnew/3.13.rst
index bfd0995752b248..b3bdc1fef6504a 100644
--- a/Doc/whatsnew/3.13.rst
+++ b/Doc/whatsnew/3.13.rst
@@ -219,6 +219,10 @@ C API Changes
 New Features
 ------------
 
+* You can now use the ``#``-specifier in :ref:`format codes <arg-parsing>`
+  without ``#define PY_SSIZE_T_CLEAN`` before ``#include <Python.h>``.
+  (Contributed by Inada Naoki in :gh:`104922`.)
+
 Porting to Python 3.13
 ----------------------
 
diff --git a/Include/abstract.h b/Include/abstract.h
index 064b0300b51ea2..73a55e1e16c397 100644
--- a/Include/abstract.h
+++ b/Include/abstract.h
@@ -135,10 +135,8 @@ extern "C" {
    This function always succeeds. */
 
 
-#ifdef PY_SSIZE_T_CLEAN
-#  define PyObject_CallFunction _PyObject_CallFunction_SizeT
-#  define PyObject_CallMethod _PyObject_CallMethod_SizeT
-#endif
+#define PyObject_CallFunction _PyObject_CallFunction_SizeT
+#define PyObject_CallMethod _PyObject_CallMethod_SizeT
 
 
 #if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03090000
@@ -195,15 +193,6 @@ PyAPI_FUNC(PyObject *) PyObject_CallMethod(PyObject *obj,
                                            const char *name,
                                            const char *format, ...);
 
-PyAPI_FUNC(PyObject *) _PyObject_CallFunction_SizeT(PyObject *callable,
-                                                    const char *format,
-                                                    ...);
-
-PyAPI_FUNC(PyObject *) _PyObject_CallMethod_SizeT(PyObject *obj,
-                                                  const char *name,
-                                                  const char *format,
-                                                  ...);
-
 /* Call a callable Python object 'callable' with a variable number of C
    arguments. The C arguments are provided as PyObject* values, terminated
    by a NULL.
diff --git a/Include/cpython/abstract.h b/Include/cpython/abstract.h
index 3b27aab2fc4798..992dd068db90ea 100644
--- a/Include/cpython/abstract.h
+++ b/Include/cpython/abstract.h
@@ -4,10 +4,6 @@
 
 /* === Object Protocol ================================================== */
 
-#ifdef PY_SSIZE_T_CLEAN
-#  define _PyObject_CallMethodId _PyObject_CallMethodId_SizeT
-#endif
-
 /* Convert keyword arguments from the FASTCALL (stack: C array, kwnames: tuple)
    format to a Python dictionary ("kwargs" dict).
 
@@ -113,11 +109,6 @@ PyAPI_FUNC(PyObject *) _PyObject_CallMethodId(PyObject *obj,
                                               _Py_Identifier *name,
                                               const char *format, ...);
 
-PyAPI_FUNC(PyObject *) _PyObject_CallMethodId_SizeT(PyObject *obj,
-                                                    _Py_Identifier *name,
-                                                    const char *format,
-                                                    ...);
-
 PyAPI_FUNC(PyObject *) _PyObject_CallMethodIdObjArgs(
     PyObject *obj,
     _Py_Identifier *name,
diff --git a/Include/cpython/modsupport.h b/Include/cpython/modsupport.h
index 88f34fe7513bf2..2cea105ce7ac97 100644
--- a/Include/cpython/modsupport.h
+++ b/Include/cpython/modsupport.h
@@ -2,19 +2,19 @@
 #  error "this header file must not be included directly"
 #endif
 
-/* If PY_SSIZE_T_CLEAN is defined, each functions treats #-specifier
-   to mean Py_ssize_t */
-#ifdef PY_SSIZE_T_CLEAN
-#define _Py_VaBuildStack                _Py_VaBuildStack_SizeT
-#else
-PyAPI_FUNC(PyObject *) _Py_VaBuildValue_SizeT(const char *, va_list);
+PyAPI_FUNC(PyObject **) _Py_VaBuildStack(
+    PyObject **small_stack,
+    Py_ssize_t small_stack_len,
+    const char *format,
+    va_list va,
+    Py_ssize_t *p_nargs);
+
 PyAPI_FUNC(PyObject **) _Py_VaBuildStack_SizeT(
     PyObject **small_stack,
     Py_ssize_t small_stack_len,
     const char *format,
     va_list va,
     Py_ssize_t *p_nargs);
-#endif
 
 PyAPI_FUNC(int) _PyArg_UnpackStack(
     PyObject *const *args,
@@ -43,13 +43,6 @@ PyAPI_FUNC(int) _PyArg_CheckPositional(const char *, Py_ssize_t,
     ((!_Py_ANY_VARARGS(max) && (min) <= (nargs) && (nargs) <= (max)) \
      || _PyArg_CheckPositional((funcname), (nargs), (min), (max)))
 
-PyAPI_FUNC(PyObject **) _Py_VaBuildStack(
-    PyObject **small_stack,
-    Py_ssize_t small_stack_len,
-    const char *format,
-    va_list va,
-    Py_ssize_t *p_nargs);
-
 typedef struct _PyArg_Parser {
     int initialized;
     const char *format;
@@ -63,13 +56,6 @@ typedef struct _PyArg_Parser {
     struct _PyArg_Parser *next;
 } _PyArg_Parser;
 
-#ifdef PY_SSIZE_T_CLEAN
-#define _PyArg_ParseTupleAndKeywordsFast  _PyArg_ParseTupleAndKeywordsFast_SizeT
-#define _PyArg_ParseStack  _PyArg_ParseStack_SizeT
-#define _PyArg_ParseStackAndKeywords  _PyArg_ParseStackAndKeywords_SizeT
-#define _PyArg_VaParseTupleAndKeywordsFast  _PyArg_VaParseTupleAndKeywordsFast_SizeT
-#endif
-
 PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywordsFast(PyObject *, PyObject *,
                                                  struct _PyArg_Parser *, ...);
 PyAPI_FUNC(int) _PyArg_ParseStack(
diff --git a/Include/modsupport.h b/Include/modsupport.h
index 4e369bd56b4d20..4c3ceca596c7ee 100644
--- a/Include/modsupport.h
+++ b/Include/modsupport.h
@@ -9,9 +9,9 @@ extern "C" {
 
 #include <stdarg.h>               // va_list
 
-/* If PY_SSIZE_T_CLEAN is defined, each functions treats #-specifier
-   to mean Py_ssize_t */
-#ifdef PY_SSIZE_T_CLEAN
+/* Since Python 3.13, each functions treats #-specifier to mean Py_ssize_t
+ * regardless PY_SSIZE_T_CLEAN is defined,
+ */
 #define PyArg_Parse                     _PyArg_Parse_SizeT
 #define PyArg_ParseTuple                _PyArg_ParseTuple_SizeT
 #define PyArg_ParseTupleAndKeywords     _PyArg_ParseTupleAndKeywords_SizeT
@@ -19,10 +19,9 @@ extern "C" {
 #define PyArg_VaParseTupleAndKeywords   _PyArg_VaParseTupleAndKeywords_SizeT
 #define Py_BuildValue                   _Py_BuildValue_SizeT
 #define Py_VaBuildValue                 _Py_VaBuildValue_SizeT
-#endif
 
 /* Due to a glitch in 3.2, the _SizeT versions weren't exported from the DLL. */
-#if !defined(PY_SSIZE_T_CLEAN) || !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
+#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000
 PyAPI_FUNC(int) PyArg_Parse(PyObject *, const char *, ...);
 PyAPI_FUNC(int) PyArg_ParseTuple(PyObject *, const char *, ...);
 PyAPI_FUNC(int) PyArg_ParseTupleAndKeywords(PyObject *, PyObject *,
@@ -34,9 +33,6 @@ PyAPI_FUNC(int) PyArg_VaParseTupleAndKeywords(PyObject *, PyObject *,
 PyAPI_FUNC(int) PyArg_ValidateKeywordArguments(PyObject *);
 PyAPI_FUNC(int) PyArg_UnpackTuple(PyObject *, const char *, Py_ssize_t, Py_ssize_t, ...);
 PyAPI_FUNC(PyObject *) Py_BuildValue(const char *, ...);
-PyAPI_FUNC(PyObject *) _Py_BuildValue_SizeT(const char *, ...);
-
-
 PyAPI_FUNC(PyObject *) Py_VaBuildValue(const char *, va_list);
 
 // Add an attribute with name 'name' and value 'obj' to the module 'mod.
diff --git a/Misc/NEWS.d/next/C API/2023-05-25-17-30-43.gh-issue-104922.V6nibW.rst b/Misc/NEWS.d/next/C API/2023-05-25-17-30-43.gh-issue-104922.V6nibW.rst
new file mode 100644
index 00000000000000..aa18824e3c5dba
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2023-05-25-17-30-43.gh-issue-104922.V6nibW.rst	
@@ -0,0 +1,2 @@
+``PY_SSIZE_T_CLEAN`` is no longer required to use '#' specifier in APIs like
+:c:func:`PyArg_ParseTuple` and :c:func:`Py_BuildValue`.
diff --git a/Misc/stable_abi.toml b/Misc/stable_abi.toml
index 48299e9b35ff97..8b4688053a4cc4 100644
--- a/Misc/stable_abi.toml
+++ b/Misc/stable_abi.toml
@@ -383,16 +383,21 @@
 
 [function.PyArg_Parse]
     added = '3.2'
+    abi_only = true
 [function.PyArg_ParseTuple]
     added = '3.2'
+    abi_only = true
 [function.PyArg_ParseTupleAndKeywords]
     added = '3.2'
+    abi_only = true
 [function.PyArg_UnpackTuple]
     added = '3.2'
 [function.PyArg_VaParse]
     added = '3.2'
+    abi_only = true
 [function.PyArg_VaParseTupleAndKeywords]
     added = '3.2'
+    abi_only = true
 [function.PyArg_ValidateKeywordArguments]
     added = '3.2'
 [data.PyBaseObject_Type]
@@ -1132,10 +1137,12 @@
     added = '3.2'
 [function.PyObject_CallFunction]
     added = '3.2'
+    abi_only = true
 [function.PyObject_CallFunctionObjArgs]
     added = '3.2'
 [function.PyObject_CallMethod]
     added = '3.2'
+    abi_only = true
 [function.PyObject_CallMethodObjArgs]
     added = '3.2'
 [function.PyObject_CallObject]
@@ -1595,6 +1602,7 @@
     added = '3.2'
 [function.Py_BuildValue]
     added = '3.2'
+    abi_only = true
 [function.Py_CompileString]
     added = '3.2'
 [function.Py_DecRef]
@@ -1661,6 +1669,7 @@
     added = '3.2'
 [function.Py_VaBuildValue]
     added = '3.2'
+    abi_only = true
 
 [function._PyErr_BadInternalCall]
     added = '3.2'
diff --git a/Objects/call.c b/Objects/call.c
index 0d548dcd5e1aed..0f6cf569121bb3 100644
--- a/Objects/call.c
+++ b/Objects/call.c
@@ -572,8 +572,9 @@ _PyObject_CallFunctionVa(PyThreadState *tstate, PyObject *callable,
     return result;
 }
 
-
-PyObject *
+// Export for the stable ABI
+#undef PyObject_CallFunction
+PyAPI_FUNC(PyObject *)
 PyObject_CallFunction(PyObject *callable, const char *format, ...)
 {
     va_list va;
@@ -634,7 +635,9 @@ callmethod(PyThreadState *tstate, PyObject* callable, const char *format, va_lis
     return _PyObject_CallFunctionVa(tstate, callable, format, va, is_size_t);
 }
 
-PyObject *
+// Export for the stable ABI
+#undef PyObject_CallMethod
+PyAPI_FUNC(PyObject *)
 PyObject_CallMethod(PyObject *obj, const char *name, const char *format, ...)
 {
     PyThreadState *tstate = _PyThreadState_GET();
@@ -724,7 +727,7 @@ _PyObject_CallMethodId(PyObject *obj, _Py_Identifier *name,
 
     va_list va;
     va_start(va, format);
-    PyObject *retval = callmethod(tstate, callable, format, va, 0);
+    PyObject *retval = callmethod(tstate, callable, format, va, 1);
     va_end(va);
 
     Py_DECREF(callable);
@@ -767,30 +770,6 @@ _PyObject_CallMethod_SizeT(PyObject *obj, const char *name,
 }
 
 
-PyObject *
-_PyObject_CallMethodId_SizeT(PyObject *obj, _Py_Identifier *name,
-                             const char *format, ...)
-{
-    PyThreadState *tstate = _PyThreadState_GET();
-    if (obj == NULL || name == NULL) {
-        return null_error(tstate);
-    }
-
-    PyObject *callable = _PyObject_GetAttrId(obj, name);
-    if (callable == NULL) {
-        return NULL;
-    }
-
-    va_list va;
-    va_start(va, format);
-    PyObject *retval = callmethod(tstate, callable, format, va, 1);
-    va_end(va);
-
-    Py_DECREF(callable);
-    return retval;
-}
-
-
 /* --- Call with "..." arguments ---------------------------------- */
 
 static PyObject *
diff --git a/Python/getargs.c b/Python/getargs.c
index 66dd90877fe6ff..214ee59d4fa285 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -12,28 +12,32 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-int PyArg_Parse(PyObject *, const char *, ...);
-int PyArg_ParseTuple(PyObject *, const char *, ...);
-int PyArg_VaParse(PyObject *, const char *, va_list);
-
-int PyArg_ParseTupleAndKeywords(PyObject *, PyObject *,
-                                const char *, char **, ...);
-int PyArg_VaParseTupleAndKeywords(PyObject *, PyObject *,
-                                const char *, char **, va_list);
-
-int _PyArg_ParseTupleAndKeywordsFast(PyObject *, PyObject *,
-                                            struct _PyArg_Parser *, ...);
-int _PyArg_VaParseTupleAndKeywordsFast(PyObject *, PyObject *,
-                                            struct _PyArg_Parser *, va_list);
+// Remove alias to _SizeT version in modsupport.h
+// These functions are kept for stable ABI.
+#undef PyArg_Parse
+#undef PyArg_ParseTuple
+#undef PyArg_ParseTupleAndKeywords
+#undef PyArg_VaParse
+#undef PyArg_VaParseTupleAndKeywords
+PyAPI_FUNC(int) PyArg_Parse(PyObject *, const char *, ...);
+PyAPI_FUNC(int) PyArg_ParseTuple(PyObject *, const char *, ...);
+PyAPI_FUNC(int) PyArg_VaParse(PyObject *, const char *, va_list);
+
+PyAPI_FUNC(int) PyArg_ParseTupleAndKeywords(
+        PyObject *, PyObject *, const char *, char **, ...);
+PyAPI_FUNC(int) PyArg_VaParseTupleAndKeywords(
+        PyObject *, PyObject *, const char *, char **, va_list);
+
+PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywordsFast(
+        PyObject *, PyObject *, struct _PyArg_Parser *, ...);
+PyAPI_FUNC(int) _PyArg_VaParseTupleAndKeywordsFast(
+        PyObject *, PyObject *, struct _PyArg_Parser *, va_list);
 
 #ifdef HAVE_DECLSPEC_DLL
 /* Export functions */
 PyAPI_FUNC(int) _PyArg_Parse_SizeT(PyObject *, const char *, ...);
 PyAPI_FUNC(int) _PyArg_ParseStack_SizeT(PyObject *const *args, Py_ssize_t nargs,
                                         const char *format, ...);
-PyAPI_FUNC(int) _PyArg_ParseStackAndKeywords_SizeT(PyObject *const *args, Py_ssize_t nargs,
-                                        PyObject *kwnames,
-                                        struct _PyArg_Parser *parser, ...);
 PyAPI_FUNC(int) _PyArg_ParseTuple_SizeT(PyObject *, const char *, ...);
 PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywords_SizeT(PyObject *, PyObject *,
                                                   const char *, char **, ...);
@@ -41,11 +45,6 @@ PyAPI_FUNC(PyObject *) _Py_BuildValue_SizeT(const char *, ...);
 PyAPI_FUNC(int) _PyArg_VaParse_SizeT(PyObject *, const char *, va_list);
 PyAPI_FUNC(int) _PyArg_VaParseTupleAndKeywords_SizeT(PyObject *, PyObject *,
                                               const char *, char **, va_list);
-
-PyAPI_FUNC(int) _PyArg_ParseTupleAndKeywordsFast_SizeT(PyObject *, PyObject *,
-                                            struct _PyArg_Parser *, ...);
-PyAPI_FUNC(int) _PyArg_VaParseTupleAndKeywordsFast_SizeT(PyObject *, PyObject *,
-                                            struct _PyArg_Parser *, va_list);
 #endif
 
 #define FLAG_COMPAT 1
@@ -151,25 +150,12 @@ _PyArg_ParseStack(PyObject *const *args, Py_ssize_t nargs, const char *format, .
     int retval;
     va_list va;
 
-    va_start(va, format);
-    retval = vgetargs1_impl(NULL, args, nargs, format, &va, 0);
-    va_end(va);
-    return retval;
-}
-
-PyAPI_FUNC(int)
-_PyArg_ParseStack_SizeT(PyObject *const *args, Py_ssize_t nargs, const char *format, ...)
-{
-    int retval;
-    va_list va;
-
     va_start(va, format);
     retval = vgetargs1_impl(NULL, args, nargs, format, &va, FLAG_SIZE_T);
     va_end(va);
     return retval;
 }
 
-
 int
 PyArg_VaParse(PyObject *args, const char *format, va_list va)
 {
@@ -657,7 +643,11 @@ convertsimple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
               char *msgbuf, size_t bufsize, freelist_t *freelist)
 {
 #define RETURN_ERR_OCCURRED return msgbuf
-    /* For # codes */
+    // For # codes
+    // Even though Python 3.13 uses ssize_t ragardless PY_SSIZE_T_CLEAN,
+    // extension compiled with Python ~3.9 may still use int version API.
+    // Remove this check after we drop supporting extension module built with
+    // Python ~3.9.
 #define REQUIRE_PY_SSIZE_T_CLEAN \
     if (!(flags & FLAG_SIZE_T)) { \
         PyErr_SetString(PyExc_SystemError, \
@@ -1368,7 +1358,6 @@ _PyArg_ParseTupleAndKeywords_SizeT(PyObject *args,
     return retval;
 }
 
-
 int
 PyArg_VaParseTupleAndKeywords(PyObject *args,
                               PyObject *keywords,
@@ -1420,60 +1409,33 @@ _PyArg_VaParseTupleAndKeywords_SizeT(PyObject *args,
     return retval;
 }
 
-PyAPI_FUNC(int)
+int
 _PyArg_ParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
                             struct _PyArg_Parser *parser, ...)
 {
     int retval;
     va_list va;
 
-    va_start(va, parser);
-    retval = vgetargskeywordsfast(args, keywords, parser, &va, 0);
-    va_end(va);
-    return retval;
-}
-
-PyAPI_FUNC(int)
-_PyArg_ParseTupleAndKeywordsFast_SizeT(PyObject *args, PyObject *keywords,
-                            struct _PyArg_Parser *parser, ...)
-{
-    int retval;
-    va_list va;
-
     va_start(va, parser);
     retval = vgetargskeywordsfast(args, keywords, parser, &va, FLAG_SIZE_T);
     va_end(va);
     return retval;
 }
 
-PyAPI_FUNC(int)
+int
 _PyArg_ParseStackAndKeywords(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
                   struct _PyArg_Parser *parser, ...)
 {
     int retval;
     va_list va;
 
-    va_start(va, parser);
-    retval = vgetargskeywordsfast_impl(args, nargs, NULL, kwnames, parser, &va, 0);
-    va_end(va);
-    return retval;
-}
-
-PyAPI_FUNC(int)
-_PyArg_ParseStackAndKeywords_SizeT(PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames,
-                        struct _PyArg_Parser *parser, ...)
-{
-    int retval;
-    va_list va;
-
     va_start(va, parser);
     retval = vgetargskeywordsfast_impl(args, nargs, NULL, kwnames, parser, &va, FLAG_SIZE_T);
     va_end(va);
     return retval;
 }
 
-
-PyAPI_FUNC(int)
+int
 _PyArg_VaParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
                             struct _PyArg_Parser *parser, va_list va)
 {
@@ -1482,20 +1444,6 @@ _PyArg_VaParseTupleAndKeywordsFast(PyObject *args, PyObject *keywords,
 
     va_copy(lva, va);
 
-    retval = vgetargskeywordsfast(args, keywords, parser, &lva, 0);
-    va_end(lva);
-    return retval;
-}
-
-PyAPI_FUNC(int)
-_PyArg_VaParseTupleAndKeywordsFast_SizeT(PyObject *args, PyObject *keywords,
-                            struct _PyArg_Parser *parser, va_list va)
-{
-    int retval;
-    va_list lva;
-
-    va_copy(lva, va);
-
     retval = vgetargskeywordsfast(args, keywords, parser, &lva, FLAG_SIZE_T);
     va_end(lva);
     return retval;
diff --git a/Python/modsupport.c b/Python/modsupport.c
index be229c987b8a78..4f9ba7de828abc 100644
--- a/Python/modsupport.c
+++ b/Python/modsupport.c
@@ -5,6 +5,13 @@
 #include "pycore_abstract.h"   // _PyIndex_Check()
 #include "pycore_object.h"     // _PyType_IsReady()
 
+// Remove alias to _SizeT version in modsupport.h
+// These two functions are kept for stable ABI.
+#undef Py_BuildValue
+#undef Py_VaBuildValue
+PyAPI_FUNC(PyObject *) Py_BuildValue(const char *, ...);
+PyAPI_FUNC(PyObject *) Py_VaBuildValue(const char *, va_list);
+
 #define FLAG_SIZE_T 1
 typedef double va_double;
 
@@ -277,6 +284,10 @@ do_mktuple(const char **p_format, va_list *p_va, char endchar, Py_ssize_t n, int
 static PyObject *
 do_mkvalue(const char **p_format, va_list *p_va, int flags)
 {
+    // Even though Python 3.13 uses ssize_t ragardless PY_SSIZE_T_CLEAN,
+    // extension compiled with Python ~3.9 may still use int version API.
+    // Remove this check after we drop supporting extension module built with
+    // Python ~3.9.
 #define ERROR_NEED_PY_SSIZE_T_CLEAN \
     { \
         PyErr_SetString(PyExc_SystemError, \
@@ -503,7 +514,6 @@ do_mkvalue(const char **p_format, va_list *p_va, int flags)
 #undef ERROR_NEED_PY_SSIZE_T_CLEAN
 }
 
-
 PyObject *
 Py_BuildValue(const char *format, ...)
 {
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 33147f012b611d..32be7ec09ebfd6 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -211,7 +211,7 @@ sys_audit_tstate(PyThreadState *ts, const char *event,
 
     /* Initialize event args now */
     if (argFormat && argFormat[0]) {
-        eventArgs = _Py_VaBuildValue_SizeT(argFormat, vargs);
+        eventArgs = Py_VaBuildValue(argFormat, vargs);
         if (eventArgs && !PyTuple_Check(eventArgs)) {
             PyObject *argTuple = PyTuple_Pack(1, eventArgs);
             Py_SETREF(eventArgs, argTuple);