diff --git a/atomicfile/atomicfile.go b/atomicfile/atomicfile.go
index dcf3c3235..f2af37182 100644
--- a/atomicfile/atomicfile.go
+++ b/atomicfile/atomicfile.go
@@ -1,4 +1,4 @@
-// Copyright 2019 Tailscale & AUTHORS. All rights reserved.
+// Copyright (c) 2019 Tailscale Inc & AUTHORS All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
diff --git a/net/nettest/pipe_test.go b/net/nettest/pipe_test.go
index f40d27c53..72a839d13 100644
--- a/net/nettest/pipe_test.go
+++ b/net/nettest/pipe_test.go
@@ -1,3 +1,7 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package nettest
 
 import (
diff --git a/scripts/check_license_headers.sh b/scripts/check_license_headers.sh
new file mode 100755
index 000000000..29bb2eee5
--- /dev/null
+++ b/scripts/check_license_headers.sh
@@ -0,0 +1,54 @@
+#!/bin/sh
+#
+# Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+#
+# check_license_headers.sh checks that all Go files in the given
+# directory tree have a correct-looking Tailscale license header.
+
+check_file() {
+    got=$1
+
+    for year in `seq 2019 2020`; do
+        want=$(cat <<EOF
+// Copyright (c) $year Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+EOF
+        )
+        if [ "$got" = "$want" ]; then
+            return 0
+        fi
+    done
+    return 1
+}
+
+if [ $# != 1 ]; then
+    echo "Usage: $0 rootdir" >&2
+    exit 1
+fi
+
+fail=0
+for file in $(find $1 -name '*.go'); do
+    case $file in
+        $1/tempfork/*)
+            # Skip, tempfork of third-party code
+        ;;
+        $1/wgengine/ifconfig_windows.go)
+            # WireGuard copyright.
+            ;;
+        *)
+            header="$(head -3 $file)"
+            if ! check_file "$header"; then
+                fail=1
+                echo "${file#$1/} doesn't have the right copyright header:"
+                echo "$header" | sed -e 's/^/    /g'
+            fi
+            ;;
+    esac
+done
+
+if [ $fail -ne 0 ]; then
+    exit 1
+fi
diff --git a/wgengine/magicsock/magicsock.go b/wgengine/magicsock/magicsock.go
index e8a2039c7..8e55e5b91 100644
--- a/wgengine/magicsock/magicsock.go
+++ b/wgengine/magicsock/magicsock.go
@@ -1,4 +1,4 @@
-// Copyright 2019 Tailscale & AUTHORS. All rights reserved.
+// Copyright (c) 2019 Tailscale Inc & AUTHORS All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.