diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 8d4807d..94bc1af 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -24,6 +24,7 @@ jobs:
       - name: Build MacTree.app
         env:
           SIGN_IDENTITY: "-"
+          UNIVERSAL: "1"
           BUILD_NUMBER: ${{ github.run_number }}
         run: |
           swift --version
@@ -32,6 +33,7 @@ jobs:
 
       - name: Smoke test
         run: |
+          lipo build/MacTree.app/Contents/MacOS/MacTree -verify_arch arm64 x86_64
           build/MacTree.app/Contents/MacOS/MacTree --bench "$GITHUB_WORKSPACE/Sources"
           codesign --verify --deep --strict build/MacTree.app
 
diff --git a/scripts/build-app.sh b/scripts/build-app.sh
index 37b6c90..a80be4a 100755
--- a/scripts/build-app.sh
+++ b/scripts/build-app.sh
@@ -5,15 +5,23 @@
 # macOS keeps the Full Disk Access grant across rebuilds (an ad-hoc signature
 # changes every build and the grant stops applying). Override with
 # SIGN_IDENTITY="<name or SHA-1>", or SIGN_IDENTITY=- for ad-hoc.
+#
+# UNIVERSAL=1 builds one binary for both Apple silicon and Intel Macs.
 set -euo pipefail
 cd "$(dirname "$0")/.."
 
-swift build -c release
+if [ -n "${UNIVERSAL:-}" ]; then
+    swift build -c release --arch arm64 --arch x86_64
+    BINARY=.build/apple/Products/Release/MacTree
+else
+    swift build -c release
+    BINARY=.build/release/MacTree
+fi
 
 APP=build/MacTree.app
 rm -rf "$APP"
 mkdir -p "$APP/Contents/MacOS" "$APP/Contents/Resources"
-cp .build/release/MacTree "$APP/Contents/MacOS/MacTree"
+cp "$BINARY" "$APP/Contents/MacOS/MacTree"
 cp Resources/Info.plist "$APP/Contents/Info.plist"
 cp -R Resources/*.lproj "$APP/Contents/Resources/"