Fourteen species of Tephritidae are newly recorded from Ontario, and alternative format keys are provided to the 31 genera and 73 species of fruit fly now known from, or likely to occur, in the province. Standard dichotomous keys to genera, and simplified field keys to genera and species are provided. Keys are illustrated with approximately 700 color photographs, and species treatments are supplemented with multiple identification aids, including Ontario distribution maps for each species. To aid in identification of immature stages, we have included sequence data (DNA barcodes) for 41 of the 73 species examined.