A security seal 10 comprises a strap portion 12 made of plastic and a lock portion 14 attached to the strap portion. The lock portion 14 includes a metal jaw with an aperture. In use, the strap portion 12 is guided into the lock portion 14 and pulled to provide an interference fit between the lock portion 14 and the strap portion 12. The security seal 10 deters tampering since efforts to pull the strap portion 12 will either result in snapping of the strap portion 12 or visible stress-induced damage to the strap portion 12.