diff --git a/Lib/test/test_ast/test_ast.py b/Lib/test/test_ast/test_ast.py
index f29f98beb2d048..459bc3ff0c06d0 100644
--- a/Lib/test/test_ast/test_ast.py
+++ b/Lib/test/test_ast/test_ast.py
@@ -954,7 +954,7 @@ def test_constant_as_unicode_name(self):
             ("None", b"N\xc2\xbane"),
         ]
         for constant in constants:
-            with self.assertRaisesRegex(ValueError,
+            with self.assertRaisesRegex(SyntaxError,
                 f"identifier field can't represent '{constant[0]}' constant"):
                 ast.parse(constant[1], mode="eval")
 
diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-03-09-17-19-04.gh-issue-145675.9YPpYi.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-09-17-19-04.gh-issue-145675.9YPpYi.rst
new file mode 100644
index 00000000000000..0774246638e267
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-03-09-17-19-04.gh-issue-145675.9YPpYi.rst
@@ -0,0 +1,2 @@
+Raise :exc:`SyntaxError` when constants ``True``, ``False`` or ``None`` are
+used as an identifier after NFKC normalization.
diff --git a/Parser/pegen.c b/Parser/pegen.c
index 7ecc55eee13775..fd7360e8350f91 100644
--- a/Parser/pegen.c
+++ b/Parser/pegen.c
@@ -539,7 +539,7 @@ _PyPegen_new_identifier(Parser *p, const char *n)
     };
     for (int i = 0; forbidden[i] != NULL; i++) {
         if (_PyUnicode_EqualToASCIIString(id, forbidden[i])) {
-            PyErr_Format(PyExc_ValueError,
+            RAISE_SYNTAX_ERROR(
                          "identifier field can't represent '%s' constant",
                          forbidden[i]);
             Py_DECREF(id);