diff --git a/app.spec b/app.spec
new file mode 100644
index 0000000..0ad0ccc
--- /dev/null
+++ b/app.spec
@@ -0,0 +1,48 @@
+# -*- mode: python ; coding: utf-8 -*-
+
+
+block_cipher = None
+
+
+a = Analysis(['diffcast/app.py'],
+             pathex=[],
+             binaries=[],
+             datas=[],
+             hiddenimports=[],
+             hookspath=[],
+             hooksconfig={},
+             runtime_hooks=[],
+             excludes=[],
+             win_no_prefer_redirects=False,
+             win_private_assemblies=False,
+             cipher=block_cipher,
+             noarchive=False)
+pyz = PYZ(a.pure, a.zipped_data,
+             cipher=block_cipher)
+
+exe = EXE(pyz,
+          a.scripts, 
+          [],
+          exclude_binaries=True,
+          name='app',
+          debug=False,
+          bootloader_ignore_signals=False,
+          strip=False,
+          upx=True,
+          console=False,
+          disable_windowed_traceback=False,
+          target_arch=None,
+          codesign_identity=None,
+          entitlements_file=None )
+coll = COLLECT(exe,
+               a.binaries,
+               a.zipfiles,
+               a.datas, 
+               strip=False,
+               upx=True,
+               upx_exclude=[],
+               name='app')
+app = BUNDLE(coll,
+             name='app.app',
+             icon=None,
+             bundle_identifier=None)
diff --git a/builddmg.sh b/builddmg.sh
new file mode 100755
index 0000000..aa7266f
--- /dev/null
+++ b/builddmg.sh
@@ -0,0 +1,16 @@
+#!/bin/sh
+mkdir -p dist/dmg
+rm -r dist/dmg/*
+cp -r dist/DiffCast.app dist/dmg
+test -f dist/DiffCast.dmg && rm dist/DiffCast.dmg
+create-dmg \
+  --volname "DiffCast" \
+  --volicon "diffcast/images/icon.icns" \
+  --window-pos 200 120 \
+  --window-size 800 400 \
+  --icon-size 100 \
+  --icon "DiffCast.app" 200 190 \
+  --hide-extension "DiffCast.app" \
+  --app-drop-link 600 185 \
+  "dist/DiffCast.dmg" \
+  "dist/dmg/"
diff --git a/diffcast.spec b/diffcast.spec
index 43d5e60..8e294c5 100644
--- a/diffcast.spec
+++ b/diffcast.spec
@@ -42,3 +42,7 @@ coll = COLLECT(exe,
                upx=True,
                upx_exclude=[],
                name='DiffCast')
+app = BUNDLE(coll,
+             name='DiffCast.app',
+             icon='diffcast/images/icon.icns',
+             bundle_identifier=None)
diff --git a/diffcast/images/icon.icns b/diffcast/images/icon.icns
new file mode 100644
index 0000000..bae34c0
Binary files /dev/null and b/diffcast/images/icon.icns differ