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 Massachusetts, Peeping Tom laws are addressed under the state's criminal statutes, specifically in Chapter 272, Section 105 of the Massachusetts General Laws. This law makes it a criminal offense to secretly photograph, videotape, or electronically surveil another person who is nude or partially nude without their knowledge and consent, especially when that person is in a place where they have a reasonable expectation of privacy, such as in a dressing room or bathroom. The law also covers the act of looking into such places with the intent to spy or invade someone's privacy. The use of devices like cameras and drones for such purposes is also prohibited. Violation of these laws can result in criminal charges, including misdemeanor or felony charges, depending on the circumstances and the severity of the offense. Additionally, Massachusetts law prohibits trespassing with the intent to commit a sexual offense, which can encompass acts of voyeurism.