diff --git a/llvm/docs/CommandGuide/lit.rst b/llvm/docs/CommandGuide/lit.rst
--- a/llvm/docs/CommandGuide/lit.rst
+++ b/llvm/docs/CommandGuide/lit.rst
@@ -43,6 +43,9 @@
 supplementing or overriding the command-line options supplied to :program:`lit`
 by ``check`` targets defined by a project's build system.
 
+:program:`lit` can also read options from response files which are specified as
+inputs using the ``@path/to/file.rsp`` syntax.
+
 Users interested in the :program:`lit` architecture or designing a
 :program:`lit` testing implementation should see :ref:`lit-infrastructure`.
 
diff --git a/llvm/utils/lit/lit/cl_arguments.py b/llvm/utils/lit/lit/cl_arguments.py
--- a/llvm/utils/lit/lit/cl_arguments.py
+++ b/llvm/utils/lit/lit/cl_arguments.py
@@ -16,7 +16,7 @@
 
 
 def parse_args():
-    parser = argparse.ArgumentParser(prog='lit')
+    parser = argparse.ArgumentParser(prog='lit', fromfile_prefix_chars='@')
     parser.add_argument('test_paths',
             nargs='+',
             metavar="TEST_PATH",