The Ontario Provincial Police (OPP) is the provincial police service of Ontario, Canada. The OPP patrols provincial highways and waterways; protects provincial government buildings and officials, with the exception of the legislative precinct; patrols unincorporated areas in northern Ontario; provides training, operational support, and funding to some Indigenous police forces; and investigates complex or multijurisdictional crimes across the province. The OPP also has a number of local mandates through contracts with municipal governments and First Nations, where it acts as the local police force and provides front-line services.

State police, provincial police or regional police are a type of sub-national territorial police force found in nations organized as federations, typically in North America, South Asia, and Oceania. These forces typically have jurisdiction over the relevant sub-national jurisdiction, and may cooperate in law enforcement activities with municipal or national police where either exist.