diff --git a/CHANGES/9406.misc.rst b/CHANGES/9406.misc.rst
new file mode 100644
index 0000000000..0a0f7e7867
--- /dev/null
+++ b/CHANGES/9406.misc.rst
@@ -0,0 +1 @@
+Reduced memory required for timer objects created during the client request lifecycle -- by :user:`bdraco`.
diff --git a/CHANGES/9407.misc.rst b/CHANGES/9407.misc.rst
new file mode 100644
index 0000000000..d2a4e1e3ae
--- /dev/null
+++ b/CHANGES/9407.misc.rst
@@ -0,0 +1 @@
+Reduced memory required for stream objects created during the client request lifecycle -- by :user:`bdraco`.
diff --git a/aiohttp/client_reqrep.py b/aiohttp/client_reqrep.py
index c077e2f498..6468b2de3c 100644
--- a/aiohttp/client_reqrep.py
+++ b/aiohttp/client_reqrep.py
@@ -751,6 +751,9 @@ async def _on_headers_request_sent(
             await trace.send_request_headers(method, url, headers)
 
 
+_CONNECTION_CLOSED_EXCEPTION = ClientConnectionError("Connection closed")
+
+
 class ClientResponse(HeadersMixin):
     # Some of these attributes are None when created,
     # but will be set by the start() method.
@@ -1106,7 +1109,7 @@ def _notify_content(self) -> None:
         content = self.content
         # content can be None here, but the types are cheated elsewhere.
         if content and content.exception() is None:  # type: ignore[truthy-bool]
-            set_exception(content, ClientConnectionError("Connection closed"))
+            set_exception(content, _CONNECTION_CLOSED_EXCEPTION)
         self._released = True
 
     async def wait_for_close(self) -> None:
diff --git a/aiohttp/helpers.py b/aiohttp/helpers.py
index 8474bb735c..ec67abf5eb 100644
--- a/aiohttp/helpers.py
+++ b/aiohttp/helpers.py
@@ -596,6 +596,8 @@ def calculate_timeout_when(
 class TimeoutHandle:
     """Timeout handle"""
 
+    __slots__ = ("_timeout", "_loop", "_ceil_threshold", "_callbacks")
+
     def __init__(
         self,
         loop: asyncio.AbstractEventLoop,
@@ -644,11 +646,17 @@ def __call__(self) -> None:
 
 
 class BaseTimerContext(ContextManager["BaseTimerContext"]):
+
+    __slots__ = ()
+
     def assert_timeout(self) -> None:
         """Raise TimeoutError if timeout has been exceeded."""
 
 
 class TimerNoop(BaseTimerContext):
+
+    __slots__ = ()
+
     def __enter__(self) -> BaseTimerContext:
         return self
 
@@ -664,6 +672,8 @@ def __exit__(
 class TimerContext(BaseTimerContext):
     """Low resolution timeout context manager"""
 
+    __slots__ = ("_loop", "_tasks", "_cancelled", "_cancelling")
+
     def __init__(self, loop: asyncio.AbstractEventLoop) -> None:
         self._loop = loop
         self._tasks: List[asyncio.Task[Any]] = []
diff --git a/aiohttp/streams.py b/aiohttp/streams.py
index d47ca014a1..b611dc198d 100644
--- a/aiohttp/streams.py
+++ b/aiohttp/streams.py
@@ -42,6 +42,9 @@ class EofStream(Exception):
 
 
 class AsyncStreamIterator(Generic[_T]):
+
+    __slots__ = ("read_func",)
+
     def __init__(self, read_func: Callable[[], Awaitable[_T]]) -> None:
         self.read_func = read_func
 
@@ -59,6 +62,9 @@ async def __anext__(self) -> _T:
 
 
 class ChunkTupleAsyncStreamIterator:
+
+    __slots__ = ("_stream",)
+
     def __init__(self, stream: "StreamReader") -> None:
         self._stream = stream
 
@@ -73,6 +79,9 @@ async def __anext__(self) -> Tuple[bytes, bool]:
 
 
 class AsyncStreamReaderMixin:
+
+    __slots__ = ()
+
     def __aiter__(self) -> AsyncStreamIterator[bytes]:
         return AsyncStreamIterator(self.readline)  # type: ignore[attr-defined]
 
@@ -107,7 +116,25 @@ class StreamReader(AsyncStreamReaderMixin):
 
     """
 
-    total_bytes = 0
+    __slots__ = (
+        "_protocol",
+        "_low_water",
+        "_high_water",
+        "_loop",
+        "_size",
+        "_cursor",
+        "_http_chunk_splits",
+        "_buffer",
+        "_buffer_offset",
+        "_eof",
+        "_waiter",
+        "_eof_waiter",
+        "_exception",
+        "_timer",
+        "_eof_callbacks",
+        "_eof_counter",
+        "total_bytes",
+    )
 
     def __init__(
         self,
@@ -134,6 +161,8 @@ def __init__(
         self._exception: Optional[Union[Type[BaseException], BaseException]] = None
         self._timer = TimerNoop() if timer is None else timer
         self._eof_callbacks: List[Callable[[], None]] = []
+        self._eof_counter = 0
+        self.total_bytes = 0
 
     def __repr__(self) -> str:
         info = [self.__class__.__name__]
@@ -505,6 +534,9 @@ def _read_nowait(self, n: int) -> bytes:
 
 
 class EmptyStreamReader(StreamReader):  # lgtm [py/missing-call-to-init]
+
+    __slots__ = ("_read_eof_chunk",)
+
     def __init__(self) -> None:
         self._read_eof_chunk = False
 
diff --git a/pyproject.toml b/pyproject.toml
index c4f6587a75..8b83775c74 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -82,3 +82,8 @@ skip = "pp*"
 [tool.codespell]
 skip = '.git,*.pdf,*.svg,Makefile,CONTRIBUTORS.txt,venvs,_build'
 ignore-words-list = 'te,assertIn'
+
+[tool.slotscheck]
+# TODO(3.13): Remove aiohttp.helpers once https://github.com/python/cpython/pull/106771
+# is available in all supported cpython versions
+exclude-modules = "(^aiohttp\\.helpers)"