Peeping Tom laws—also known as voyeurism laws or invasion of privacy laws—generally make it illegal and a criminal offense to peek into windows or doors on private property to view a person who is fully or partially naked for the purpose of sexual desire or gratification.

Peeping Tom laws vary from state to state and some states require that the victim not realize he or she was being viewed and that the victim had a reasonable expectation of privacy (was in a place where it was reasonable to expect privacy). And some states specifically address the use of unmanned aircraft (drones), cameras, video cameras, and binoculars in connection with such peeping. Some state statutes specifically prohibit peeking into bathrooms, dressing rooms, showers, and baths. And some states characterize this criminal offense as trespassing with the intent to peer or peep.

Peeping Tom laws are located in a state’s statutes—often in the penal or criminal code.

In Missouri, Peeping Tom laws are addressed under the state's invasion of privacy statutes. Missouri law makes it a criminal offense to knowingly view, photograph, or film another person without that person's consent while the person is in a state of full or partial nudity and is in a place where he or she would have a reasonable expectation of privacy. This includes private dwellings, bathrooms, changing rooms, and similar areas where one expects privacy. The use of devices like cameras, binoculars, or other technology to enhance or facilitate this invasion of privacy is also prohibited. Additionally, Missouri law has provisions that address trespassing with the intent to invade someone's privacy. The severity of the offense can range from a misdemeanor to a felony, depending on the circumstances and whether it is a first or subsequent offense. It's important to note that the victim does not need to be aware that they are being viewed for the offense to occur. The law is designed to protect the reasonable expectation of privacy that individuals have in certain locations.