The article examines the paradiplomatic activity of the Canadian province Ontario which is one of the most active entities of Canada in the international arena of the XXI century. The author pays attention to the main Ontario's directions of international activity and the relation of the province's paradiplomacy with the policy of the Federal center in the XXI century. The article also considers the main reasons for the development of paradiplomacy in Canada. As a result, it is concluded that Ontario is a successful foreign policy actor; the province finds compromises with the Federal center, thanks to this approach, it builds strong relations with other international actors: traditionally with the United States, and as the alternative direction - China.