diff --git a/pkgs/misc/emulators/np2kai/default.nix b/pkgs/misc/emulators/np2kai/default.nix
new file mode 100644
index 000000000000..245bad1d535f
--- /dev/null
+++ b/pkgs/misc/emulators/np2kai/default.nix
@@ -0,0 +1,196 @@
+{ stdenv
+, lib
+, fetchFromGitHub
+, enable16Bit ? true
+, enable32Bit ? true
+
+, enableSDL ? true
+, withSDLVersion ? "2"
+, SDL
+, SDL_ttf
+, SDL_mixer
+, SDL2
+, SDL2_ttf
+, SDL2_mixer
+
+, enableX11 ? stdenv.hostPlatform.isLinux
+, automake
+, autoconf
+, autoconf-archive
+, libtool
+, pkg-config
+, unzip
+, gtk2
+, libusb1
+, libXxf86vm
+, nasm
+, libICE
+, libSM
+
+  # HAXM build succeeds but the binary segfaults, seemingly due to the missing HAXM kernel module
+  # Enable once there is a HAXM kernel module option in NixOS? Or somehow bind it to the system kernel having HAXM?
+  # Or leave it disabled by default?
+  # https://github.com/intel/haxm/blob/master/docs/manual-linux.md
+, enableHAXM ? false
+}:
+
+assert lib.assertMsg (enable16Bit || enable32Bit)
+  "Must enable 16-Bit and/or 32-Bit system variant.";
+assert lib.assertMsg (enableSDL || enableX11)
+  "Must enable SDL and/or X11 graphics interfaces.";
+assert lib.assertOneOf "withSDLVersion" withSDLVersion [ "1" "2" ];
+assert enableHAXM -> (lib.assertMsg enableX11
+  "Must enable X11 graphics interface for HAXM build.");
+let
+  inherit (lib) optional optionals optionalString;
+  inherit (lib.strings) concatStringsSep concatMapStringsSep;
+  isSDL2 = (withSDLVersion == "2");
+  sdlInfix = optionalString isSDL2 "2";
+  sdlDeps1 = [
+    SDL
+    SDL_ttf
+    SDL_mixer
+  ];
+  sdlDeps2 = [
+    SDL2
+    SDL2_ttf
+    SDL2_mixer
+  ];
+  sdlDepsBuildonly = if isSDL2 then sdlDeps1 else sdlDeps2;
+  sdlDepsTarget = if isSDL2 then sdlDeps2 else sdlDeps1;
+  sdlMakefileSuffix =
+    if stdenv.hostPlatform.isWindows then "win"
+    else if stdenv.hostPlatform.isDarwin then "mac"
+    else "unix";
+  sdlMakefiles = concatMapStringsSep " " (x: x + "." + sdlMakefileSuffix)
+    (optionals enable16Bit [
+      "Makefile"
+    ] ++ optionals enable32Bit [
+      "Makefile21"
+    ]);
+  sdlBuildFlags = concatStringsSep " "
+    (optionals enableSDL [
+      "SDL_VERSION=${withSDLVersion}"
+    ]);
+  sdlBins = concatStringsSep " "
+    (optionals enable16Bit [
+      "np2kai"
+    ] ++ optionals enable32Bit [
+      "np21kai"
+    ]);
+  x11ConfigureFlags = concatStringsSep " "
+    ((
+      if ((enableHAXM && (enable16Bit || enable32Bit)) || (enable16Bit && enable32Bit)) then [
+        "--enable-build-all"
+      ] else if enableHAXM then [
+        "--enable-haxm"
+      ] else if enable32Bit then [
+        "--enable-ia32"
+      ] else [ ]
+    ) ++ optionals (!isSDL2) [
+      "--enable-sdl"
+      "--enable-sdlmixer"
+      "--enable-sdlttf"
+
+      "--enable-sdl2=no"
+      "--enable-sdl2mixer=no"
+      "--enable-sdl2ttf=no"
+    ]);
+  x11BuildFlags = concatStringsSep " " [
+    "SDL2_CONFIG=sdl2-config"
+    "SDL_CONFIG=sdl-config"
+    "SDL_CFLAGS=\"$(sdl${sdlInfix}-config --cflags)\""
+    "SDL_LIBS=\"$(sdl${sdlInfix}-config --libs) -lSDL${sdlInfix}_mixer -lSDL${sdlInfix}_ttf\""
+  ];
+  x11Bins = concatStringsSep " "
+    (optionals enable16Bit [
+      "xnp2kai"
+    ] ++ optionals enable32Bit [
+      "xnp21kai"
+    ] ++ optionals enableHAXM [
+      "xnp21kai_haxm"
+    ]);
+in
+stdenv.mkDerivation rec {
+  pname = "np2kai";
+  version = "0.86rev22"; #update src.rev to commit rev accordingly
+
+  src = fetchFromGitHub rec {
+    owner = "AZO234";
+    repo = "NP2kai";
+    rev = "4a317747724669343e4c33ebdd34783fb7043221";
+    sha256 = "0kxysxhx6jyk82mx30ni0ydzmwdcbnlxlnarrlq018rsnwb4md72";
+  };
+
+  configurePhase = ''
+    export GIT_VERSION=${builtins.substring 0 7 src.rev}
+    buildFlags="$buildFlags ''${enableParallelBuilding:+-j$NIX_BUILD_CORES -l$NIX_BUILD_CORES}"
+  '' + optionalString enableX11 ''
+    cd x11
+    substituteInPlace Makefile.am \
+      --replace 'GIT_VERSION :=' 'GIT_VERSION ?='
+    ./autogen.sh ${x11ConfigureFlags}
+    ./configure ${x11ConfigureFlags}
+    cd ..
+  '';
+
+  nativeBuildInputs = sdlDepsBuildonly
+    ++ optionals enableX11 [
+    automake
+    autoconf
+    autoconf-archive
+    libtool
+    pkg-config
+    unzip
+    nasm
+  ];
+
+  buildInputs = sdlDepsTarget
+    ++ optionals enableX11 [
+    gtk2
+    libICE
+    libSM
+    libusb1
+    libXxf86vm
+  ];
+
+  enableParallelBuilding = true;
+
+  buildPhase = optionalString enableSDL ''
+    cd sdl2
+    for mkfile in ${sdlMakefiles}; do
+      substituteInPlace $mkfile \
+        --replace 'GIT_VERSION :=' 'GIT_VERSION ?='
+      echo make -f $mkfile $buildFlags ${sdlBuildFlags} clean
+      make -f $mkfile $buildFlags ${sdlBuildFlags} clean
+      make -f $mkfile $buildFlags ${sdlBuildFlags}
+    done
+    cd ..
+  '' + optionalString enableX11 ''
+    cd x11
+    make $buildFlags ${x11BuildFlags}
+    cd ..
+  '';
+
+  installPhase = optionalString enableSDL ''
+    cd sdl2
+    for emu in ${sdlBins}; do
+      install -D -m 755 $emu $out/bin/$emu
+    done
+    cd ..
+  '' + optionalString enableX11 ''
+    cd x11
+    for emu in ${x11Bins}; do
+      install -D -m 755 $emu $out/bin/$emu
+    done
+    cd ..
+  '';
+
+  meta = with lib; {
+    description = "A PC-9801 series emulator.";
+    homepage = "https://github.com/AZO234/NP2kai";
+    license = licenses.mit;
+    maintainers = with maintainers; [ OPNA2608 ];
+    platforms = platforms.x86;
+  };
+}
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 4cfd71b806c9..4377454d6289 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -4851,6 +4851,8 @@ in
 
   now-cli = callPackage ../development/web/now-cli {};
 
+  np2kai = callPackage ../misc/emulators/np2kai { };
+
   file-rename = callPackage ../tools/filesystems/file-rename { };
 
   kea = callPackage ../tools/networking/kea { };