'Third party policing' describes police efforts to persuade or coerce third parties, such as landlords, parents, local governments and other regulators, and business owners, to take some responsibility for preventing crime or reducing crime problems. In third party policing, the police create crime control guardians in locations or situations where crime control guardianship was previously absent. Sometimes this results from cooperative consultation with community members. At other times, the police use coercive threats, with the backing of a range of civil and regulatory laws, to engage third parties into taking some crime control responsibility. Our paper describes the dimensions of third party policing and identifies its prospects and challenges, including its implications for regulators.