The Ontario Provincial Police (O.P.P.) (French: Police provinciale de l'Ontario) is the Provincial Police force for the province of Ontario, Canada.

The OPP is the largest deployed police force in Ontario and the second largest in Canada. The service is responsible for providing policing services throughout the province in areas lacking local police forces. It also provides specialized support to smaller municipal police forces, investigates provincewide and cross-jurisdictional crimes, patrols provincial highways (including Ontario's 400-Series Highways) and is responsible for many of the waterways in the province. The OPP also works with other provincial agencies, including the Ministry of Transportation and Ministry of Natural Resources to enforce highway safety and conservation regulations, respectively. Finally, OPP officers provide security at the Ontario Legislature at Queen's Park in Toronto.

The OPP is one of three provincial police forces in Canada. The others are the Royal Newfoundland Constabulary in Newfoundland and Labrador and the Sûreté du Québec.