diff --git a/CHANGES/6721.misc b/CHANGES/6721.misc
new file mode 100644
index 00000000000..7a17708f0fb
--- /dev/null
+++ b/CHANGES/6721.misc
@@ -0,0 +1 @@
+Remove unused argument `max_headers` of HeadersParser.
diff --git a/aiohttp/http_parser.py b/aiohttp/http_parser.py
index 5a756be8a46..dd1c0850e5e 100644
--- a/aiohttp/http_parser.py
+++ b/aiohttp/http_parser.py
@@ -125,11 +125,9 @@ class HeadersParser:
     def __init__(
         self,
         max_line_size: int = 8190,
-        max_headers: int = 32768,
         max_field_size: int = 8190,
     ) -> None:
         self.max_line_size = max_line_size
-        self.max_headers = max_headers
         self.max_field_size = max_field_size
 
     def parse_headers(
@@ -222,7 +220,6 @@ def __init__(
         loop: asyncio.AbstractEventLoop,
         limit: int,
         max_line_size: int = 8190,
-        max_headers: int = 32768,
         max_field_size: int = 8190,
         timer: Optional[BaseTimerContext] = None,
         code: Optional[int] = None,
@@ -236,7 +233,6 @@ def __init__(
         self.protocol = protocol
         self.loop = loop
         self.max_line_size = max_line_size
-        self.max_headers = max_headers
         self.max_field_size = max_field_size
         self.timer = timer
         self.code = code
@@ -253,7 +249,7 @@ def __init__(
         self._payload_parser: Optional[HttpPayloadParser] = None
         self._auto_decompress = auto_decompress
         self._limit = limit
-        self._headers_parser = HeadersParser(max_line_size, max_headers, max_field_size)
+        self._headers_parser = HeadersParser(max_line_size, max_field_size)
 
     @abc.abstractmethod
     def parse_message(self, lines: List[bytes]) -> _MsgT:
diff --git a/aiohttp/web_protocol.py b/aiohttp/web_protocol.py
index aa4ff64dbcd..45b6f423fc1 100644
--- a/aiohttp/web_protocol.py
+++ b/aiohttp/web_protocol.py
@@ -142,8 +142,6 @@ class RequestHandler(BaseProtocol):
 
     max_field_size -- Optional maximum header field size
 
-    max_headers -- Optional maximum header size
-
     timeout_ceil_threshold -- Optional value to specify
                               threshold to ceil() timeout
                               values
@@ -191,7 +189,6 @@ def __init__(
         access_log: Logger = access_logger,
         access_log_format: str = AccessLogger.LOG_FORMAT,
         max_line_size: int = 8190,
-        max_headers: int = 32768,
         max_field_size: int = 8190,
         lingering_time: float = 10.0,
         read_bufsize: int = 2**16,
@@ -228,7 +225,6 @@ def __init__(
             read_bufsize,
             max_line_size=max_line_size,
             max_field_size=max_field_size,
-            max_headers=max_headers,
             payload_exception=RequestPayloadError,
             auto_decompress=auto_decompress,
         )
diff --git a/docs/web_reference.rst b/docs/web_reference.rst
index 9cb92cf337c..353cee6187e 100644
--- a/docs/web_reference.rst
+++ b/docs/web_reference.rst
@@ -2598,7 +2598,6 @@ application on specific TCP or Unix socket, e.g.::
         :attr:`helpers.AccessLogger.LOG_FORMAT`.
    :param int max_line_size: Optional maximum header line size. Default:
         ``8190``.
-   :param int max_headers: Optional maximum header size. Default: ``32768``.
    :param int max_field_size: Optional maximum header field size. Default:
         ``8190``.
 
diff --git a/tests/test_http_parser.py b/tests/test_http_parser.py
index 13c7ce323d1..c5de9c319cf 100644
--- a/tests/test_http_parser.py
+++ b/tests/test_http_parser.py
@@ -58,7 +58,6 @@ def parser(loop: Any, protocol: Any, request: Any):
         loop,
         2**16,
         max_line_size=8190,
-        max_headers=32768,
         max_field_size=8190,
     )
 
@@ -77,7 +76,6 @@ def response(loop: Any, protocol: Any, request: Any):
         loop,
         2**16,
         max_line_size=8190,
-        max_headers=32768,
         max_field_size=8190,
     )
 
@@ -898,7 +896,6 @@ def test_parse_bad_method_for_c_parser_raises(loop: Any, protocol: Any) -> None:
         loop,
         2**16,
         max_line_size=8190,
-        max_headers=32768,
         max_field_size=8190,
     )