diff --git a/cmd/gomobile/build.go b/cmd/gomobile/build.go
index 423da7f..7543a2b 100644
--- a/cmd/gomobile/build.go
+++ b/cmd/gomobile/build.go
@@ -24,7 +24,7 @@
 var cmdBuild = &command{
 	run:   runBuild,
 	Name:  "build",
-	Usage: "[-target android|ios] [-o output] [build flags] [package]",
+	Usage: "[-target android|ios] [-o output] [-bundleid bundleId] [build flags] [package]",
 	Short: "compile android APK and iOS app",
 	Long: `
 Build compiles and encodes the app named by the import path.
@@ -47,6 +47,9 @@
 If the package directory contains an assets subdirectory, its contents
 are copied into the output.
 
+The -bundleid flag is for -target ios only and sets the bundle ID to use 
+with the app; defaults to "org.golang.todo".
+
 The -o flag specifies the output file name. If not specified, the
 output file name depends on the package built.
 
@@ -118,7 +121,7 @@
 			}
 			return goBuild(pkg.ImportPath, darwinArm64Env)
 		}
-		nmpkgs, err = goIOSBuild(pkg)
+		nmpkgs, err = goIOSBuild(pkg, buildBundleID)
 		if err != nil {
 			return err
 		}
@@ -205,16 +208,17 @@
 
 // "Build flags", used by multiple commands.
 var (
-	buildA       bool   // -a
-	buildI       bool   // -i
-	buildN       bool   // -n
-	buildV       bool   // -v
-	buildX       bool   // -x
-	buildO       string // -o
-	buildGcflags string // -gcflags
-	buildLdflags string // -ldflags
-	buildTarget  string // -target
-	buildWork    bool   // -work
+	buildA        bool   // -a
+	buildI        bool   // -i
+	buildN        bool   // -n
+	buildV        bool   // -v
+	buildX        bool   // -x
+	buildO        string // -o
+	buildGcflags  string // -gcflags
+	buildLdflags  string // -ldflags
+	buildTarget   string // -target
+	buildWork     bool   // -work
+	buildBundleID string // -bundleid
 )
 
 func addBuildFlags(cmd *command) {
@@ -222,6 +226,7 @@
 	cmd.flag.StringVar(&buildGcflags, "gcflags", "", "")
 	cmd.flag.StringVar(&buildLdflags, "ldflags", "", "")
 	cmd.flag.StringVar(&buildTarget, "target", "android", "")
+	cmd.flag.StringVar(&buildBundleID, "bundleid", "org.golang.todo", "")
 
 	cmd.flag.BoolVar(&buildA, "a", false, "")
 	cmd.flag.BoolVar(&buildI, "i", false, "")
diff --git a/cmd/gomobile/build_darwin_test.go b/cmd/gomobile/build_darwin_test.go
index 0cb6754..00097a0 100644
--- a/cmd/gomobile/build_darwin_test.go
+++ b/cmd/gomobile/build_darwin_test.go
@@ -33,7 +33,29 @@
 		t.Fatal(err)
 	}
 
-	diff, err := diffOutput(buf.String(), iosBuildTmpl)
+	teamID, err := detectTeamID()
+	if err != nil {
+		t.Fatalf("detecting team ID failed: %v", err)
+	}
+
+	data := struct {
+		outputData
+		TeamID string
+	}{
+		outputData: defaultOutputData(),
+		TeamID:     teamID,
+	}
+
+	got := filepath.ToSlash(buf.String())
+
+	wantBuf := new(bytes.Buffer)
+
+	if err := iosBuildTmpl.Execute(wantBuf, data); err != nil {
+		t.Fatalf("computing diff failed: %v", err)
+	}
+
+	diff, err := diff(got, wantBuf.String())
+
 	if err != nil {
 		t.Fatalf("computing diff failed: %v", err)
 	}
@@ -54,6 +76,6 @@
 GOOS=darwin GOARCH=arm64 CC=clang-iphoneos CXX=clang-iphoneos CGO_CFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch arm64 CGO_LDFLAGS=-isysroot=iphoneos -miphoneos-version-min=6.1 -arch arm64 CGO_ENABLED=1 go build -pkgdir=$GOMOBILE/pkg_darwin_arm64 -tags tag1 ios -x -o=$WORK/arm64 golang.org/x/mobile/example/basic
 xcrun lipo -create $WORK/arm $WORK/arm64 -o $WORK/main/main
 mkdir -p $WORK/main/assets
-xcrun xcodebuild -configuration Release -project $WORK/main.xcodeproj
+xcrun xcodebuild -configuration Release -project $WORK/main.xcodeproj -allowProvisioningUpdates DEVELOPMENT_TEAM={{.TeamID}}
 mv $WORK/build/Release-iphoneos/main.app basic.app
 `))
diff --git a/cmd/gomobile/build_iosapp.go b/cmd/gomobile/build_iosapp.go
index 0b2a923..3146173 100644
--- a/cmd/gomobile/build_iosapp.go
+++ b/cmd/gomobile/build_iosapp.go
@@ -6,6 +6,8 @@
 
 import (
 	"bytes"
+	"crypto/x509"
+	"encoding/pem"
 	"fmt"
 	"go/build"
 	"io/ioutil"
@@ -17,7 +19,7 @@
 	"text/template"
 )
 
-func goIOSBuild(pkg *build.Package) (map[string]bool, error) {
+func goIOSBuild(pkg *build.Package, bundleID string) (map[string]bool, error) {
 	src := pkg.ImportPath
 	if buildO != "" && !strings.HasSuffix(buildO, ".app") {
 		return nil, fmt.Errorf("-o must have an .app for -target=ios")
@@ -31,7 +33,7 @@
 	infoplist := new(bytes.Buffer)
 	if err := infoplistTmpl.Execute(infoplist, infoplistTmplData{
 		// TODO: better bundle id.
-		BundleID: "org.golang.todo." + productName,
+		BundleID: bundleID + "." + productName,
 		Name:     strings.Title(path.Base(pkg.ImportPath)),
 	}); err != nil {
 		return nil, err
@@ -94,12 +96,22 @@
 		return nil, err
 	}
 
+	// Detect the team ID
+	teamID, err := detectTeamID()
+	if err != nil {
+		return nil, err
+	}
+
 	// Build and move the release build to the output directory.
-	cmd = exec.Command(
-		"xcrun", "xcodebuild",
+	cmdStrings := []string{
+		"xcodebuild",
 		"-configuration", "Release",
-		"-project", tmpdir+"/main.xcodeproj",
-	)
+		"-project", tmpdir + "/main.xcodeproj",
+		"-allowProvisioningUpdates",
+		"DEVELOPMENT_TEAM=" + teamID,
+	}
+
+	cmd = exec.Command("xcrun", cmdStrings...)
 	if err := runCmd(cmd); err != nil {
 		return nil, err
 	}
@@ -133,6 +145,39 @@
 	return nmpkgs, nil
 }
 
+func detectTeamID() (string, error) {
+	// Grabs the first certificate for "iPhone Developer"; will not work if there
+	// are multiple certificates and the first is not desired.
+	cmd := exec.Command(
+		"security", "find-certificate",
+		"-c", "iPhone Developer", "-p",
+	)
+	pemString, err := cmd.Output()
+	if err != nil {
+		err = fmt.Errorf("failed to pull the signing certificate to determine your team ID: %v", err)
+		return "", err
+	}
+
+	block, _ := pem.Decode(pemString)
+	if block == nil {
+		err = fmt.Errorf("failed to decode the PEM to determine your team ID: %s", pemString)
+		return "", err
+	}
+
+	cert, err := x509.ParseCertificate(block.Bytes)
+	if err != nil {
+		err = fmt.Errorf("failed to parse your signing certificate to determine your team ID: %v", err)
+		return "", err
+	}
+
+	if len(cert.Subject.OrganizationalUnit) == 0 {
+		err = fmt.Errorf("the signing certificate has no organizational unit (team ID).")
+		return "", err
+	}
+
+	return cert.Subject.OrganizationalUnit[0], nil
+}
+
 func iosCopyAssets(pkg *build.Package, xcodeProjDir string) error {
 	dstAssets := xcodeProjDir + "/main/assets"
 	if err := mkdir(dstAssets); err != nil {