diff --git a/stdlib/binascii.pyi b/stdlib/binascii.pyi
index 53f72ad6a..0656794d3 100644
--- a/stdlib/binascii.pyi
+++ b/stdlib/binascii.pyi
@@ -14,7 +14,12 @@ if sys.version_info >= (3, 7):
 else:
     def b2a_uu(__data: ReadableBuffer) -> bytes: ...
 
-def a2b_base64(__data: _AsciiBuffer) -> bytes: ...
+if sys.version_info >= (3, 11):
+    def a2b_base64(__data: _AsciiBuffer, *, strict_mode: bool = ...) -> bytes: ...
+
+else:
+    def a2b_base64(__data: _AsciiBuffer) -> bytes: ...
+
 def b2a_base64(__data: ReadableBuffer, *, newline: bool = ...) -> bytes: ...
 def a2b_qp(data: _AsciiBuffer, header: bool = ...) -> bytes: ...
 def b2a_qp(data: ReadableBuffer, quotetabs: bool = ..., istext: bool = ..., header: bool = ...) -> bytes: ...
diff --git a/tests/stubtest_allowlists/py311.txt b/tests/stubtest_allowlists/py311.txt
index 5fcb93af0..70c152a21 100644
--- a/tests/stubtest_allowlists/py311.txt
+++ b/tests/stubtest_allowlists/py311.txt
@@ -32,7 +32,6 @@ asyncio.sslproto._SSLProtocolTransport.get_read_buffer_size
 asyncio.sslproto._SSLProtocolTransport.set_read_buffer_limits
 asyncio.sslproto.add_flowcontrol_defaults
 bdb.Breakpoint.clearBreakpoints
-binascii.a2b_base64
 builtins.dict.get
 concurrent.futures.ProcessPoolExecutor.__init__
 concurrent.futures.process.ProcessPoolExecutor.__init__