Dressing up like police officers is an irreverent, funny option for teen Halloween costumes. It's easy to find premade law enforcement costumes at most party stores. Teens can also head to local uniform supply stores or cobble together an outfit from their own slacks and button down shirts. Aviator-style sunglasses are the most important accessory when dressing up like a police officer. Guys might like to draw on a mustache as well. Toy guns and badges add a little more realism to the outfit, although teens should be careful about the venues they enter with their pretend firearms.