diff --git a/pyproject.toml b/pyproject.toml
index 17ee643c5..6dd4916db 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,7 +39,7 @@ dependencies = [
 [project.optional-dependencies]
 standard = [
     "colorama>=0.4;sys_platform == 'win32'",
-    "httptools>=0.5.0",
+    "httptools>=0.6.3",
     "python-dotenv>=0.13",
     "PyYAML>=5.1",
     "uvloop>=0.14.0,!=0.15.0,!=0.15.1; sys_platform != 'win32' and (sys_platform != 'cygwin' and platform_python_implementation != 'PyPy')",
diff --git a/uvicorn/protocols/http/httptools_impl.py b/uvicorn/protocols/http/httptools_impl.py
index 00f1fb720..f3396a768 100644
--- a/uvicorn/protocols/http/httptools_impl.py
+++ b/uvicorn/protocols/http/httptools_impl.py
@@ -58,6 +58,14 @@ def __init__(
         self.access_logger = logging.getLogger("uvicorn.access")
         self.access_log = self.access_logger.hasHandlers()
         self.parser = httptools.HttpRequestParser(self)
+
+        try:
+            # Enable dangerous leniencies to allow server to a response on the first request from a pipelined request.
+            self.parser.set_dangerous_leniencies(lenient_data_after_close=True)
+        except AttributeError:  # pragma: no cover
+            # httptools < 0.6.3
+            pass
+
         self.ws_protocol_class = config.ws_protocol_class
         self.root_path = config.root_path
         self.limit_concurrency = config.limit_concurrency