diff --git a/default.nix b/default.nix
index 303604e..2ce86ce 100644
--- a/default.nix
+++ b/default.nix
@@ -23,6 +23,8 @@ self: super:
 
   picoquic = super.callPackage ./pkgs/picoquic/default.nix { };
 
+  quicly = super.callPackage ./pkgs/quicly/default.nix { };
+
   shinto-cli = super.callPackage ./pkgs/shinto-cli { };
 
   ui = super.callPackage ./pkgs/nim-packages/ui.nix { };
diff --git a/pkgs/quicly/default.nix b/pkgs/quicly/default.nix
new file mode 100644
index 0000000..18e6b4b
--- /dev/null
+++ b/pkgs/quicly/default.nix
@@ -0,0 +1,80 @@
+{ stdenv
+, cmake
+, openssl
+, perl
+, fetchFromGitHub
+}:
+
+let
+  picotls = fetchFromGitHub {
+    owner = "h2o";
+    repo = "picotls";
+    rev = "9238121fa7788e8642072b6d4d1a2f2fb71db242";
+    sha256 = "0yam62yd606q8v515r74l110gmch4i4bif9hfxn7mgvcdv979l7d";
+  };
+
+  picotest = fetchFromGitHub {
+    owner = "h2o";
+    repo = "picotest";
+    rev = "6906d90b39684b8b2c18db5b0c7412128140655d";
+    sha256 = "1z26mcg40bkrgbxgh4469y97lixls00p75k9j9dw1w18bg8mg49n";
+  };
+
+  klib = fetchFromGitHub {
+    owner = "attractivechaos";
+    repo = "klib";
+    rev = "928581a78413bed4efa956731b35b18a638f20f3";
+    sha256 = "0zzmnh6vgivrm9yky181lm1pxjz7hx98p3hs59dws3zdmv8dfvwj";
+  };
+in
+stdenv.mkDerivation rec {
+  pname = "quicly";
+  version = "20201024";
+
+  src = fetchFromGitHub {
+    owner = "h2o";
+    repo = "quicly";
+    rev = "d80c87059b6aefd8ab74c370378315f5b077b904";
+    sha256 = "0l92snfvifmblskxqsrrncjnpy9hhsi7gmvzghbsxk0vx6729h71";
+  };
+
+  outputs = [ "out" "dev" ];
+
+  nativeBuildInputs = [
+    cmake
+    perl
+  ];
+
+  buildInputs = [
+    openssl
+  ];
+
+  patchPhase = ''
+    sed -i 's|''${CMAKE_SOURCE_DIR}/deps/picotls|${picotls}|g' CMakeLists.txt
+    sed -i 's|deps/klib|${klib}|g' CMakeLists.txt
+    sed -i 's|deps/picotls|${picotls}|g' CMakeLists.txt
+    sed -i 's|deps/picotest|${picotest}|g' CMakeLists.txt
+    sed -i 's|\.\./deps/picotls|${picotls}|g' src/cli.c
+  '';
+
+  installPhase = ''
+    runHook preInstall
+
+    mv cli quicly
+    install -Dt $out/bin quicly
+    install -Dt $out/lib *.a
+    install -Dt $dev/include ../include/quicly.h
+    install -Dt $dev/include/quicly ../include/quicly/*.h
+    install -Dt $dev/include/quicly ${picotls}/include/picotls.h
+
+    runHook postInstall
+  '';
+
+  meta = with stdenv.lib; {
+    description = "A modular QUIC stack designed primarily for H2O";
+    homepage = https://github.com/h2o/quicly;
+    license = licenses.mit;
+    maintainers = with maintainers; [ royneary ];
+    platforms = platforms.linux;
+  };
+}