Monsignor Percy Johnson Catholic Secondary School is a Roman Catholic high school in the city of Toronto, Ontario, Canada part of the Toronto Catholic District School Board. It is located in the neighbourhood of Rexdale, in the former suburb of Etobicoke.

The Toronto Catholic District School Board is an English-language public-separate school board for Toronto, Ontario, Canada, headquartered in North York. It is one of the two English boards of education serving the city of Toronto. With more than 84,000 students, the TCDSB is one of the largest school boards in Canada, and is the largest publicly funded Catholic school board in the world. Until 1998, it was known as the Metropolitan Separate School Board (MSSB) as an anglophone and francophone separate school district.