Privacy is a person’s legally protected interest in preventing government or other intrusion into their homes; their communications (phone, e-mail, in-person); their luggage; certain compartments of their motor vehicle (glovebox, trunk); their personally identifiable information (PII); their body (hair, clothing, unexposed body parts); their image and likeness (through unauthorized use); and other information, places, and property (real and personal) in which persons have a reasonable expectation of privacy.

People generally do not have a right to privacy from being photographed or heard (if done without use of surreptitious electronic or other surveillance technologies) in public places—essentially, when they step outside of their home. There are exceptions to this general rule in which persons do have a right to privacy—such as in a doctor’s exam room or when making a phone call in a phone booth.

The Fourth Amendment to the United States Constitution protects people against government intrusions into their privacy.

And state and federal laws (statutes and court opinions) generally protect persons from unauthorized use of their personal information and from intrusions into their privacy by nongovernmental persons or entities. These protected privacy interests are generally limited to areas in which persons have a reasonable expectation of privacy (home, health information, image and likeness, e-mail communications, etc.)—and these laws vary from state to state.

In Montana, privacy is recognized as a legally protected interest, safeguarding individuals from unwarranted intrusions by the government and other entities into various aspects of their personal lives. This includes protection against intrusion into homes, communications, luggage, certain vehicle compartments, personally identifiable information (PII), the body, and one's image and likeness. The Fourth Amendment of the U.S. Constitution provides a broad protection against unreasonable searches and seizures by the government, reinforcing the right to privacy in areas where there is a reasonable expectation of privacy. Montana state law complements these protections, although specific statutes and court opinions may vary in their application. For instance, Montana has laws that address unauthorized use of personal information, such as the Montana Privacy in Communications Act, which protects the privacy of electronic communications. However, in public spaces, individuals generally do not have a right to privacy from being photographed or overheard, unless they are in a situation where privacy is traditionally respected, such as in a medical facility or using a private phone booth. It's important to note that while there is a reasonable expectation of privacy in certain contexts, this does not extend to all areas of life, and the specifics of these protections can differ based on state law and judicial interpretations.