Founded in 1919, has 50,000 members across Ontario. They include public high school teachers, occasional teachers, teaching assistants, and other educational and support workers.

Members of the Ontario Secondary School Teachers Federation in Lambton and Kent Counties.

Consists of over 2,000 educational workers in a variety of workplaces within the city of London and the counties of Elgin, Middlesex and Oxford.

Represents guidance counsellors and other support personnel working for the Toronto District School Board.

Serves educational workers employed by the Toronto District School Board.

Represents secondary school personnel working within the secondary school system in Durham Region. Includes news releases, upcoming events and links.

Educational workers in the Peterborough area.

Teachers in Kawartha Lakes, Haliburton and part of Muskoka.

Represents over 1000 members including both secondary school teachers and approximately 60 P.S.S.P workers.

Represents educational workers in the Kitchener-Waterloo area.

Represents local teachers. News and photos of past events are included.

Represents approximately 1000 teachers and education workers in Eastern Ontario, an area stretching from Cornwall and Hawkesbury to Gananoque and Perth.

Represents educational workers in the Hastings-Prince Edward area.

Represents secondary school teachers of the Near North District School Board in matters related to collective bargaining, contract maintenance and professional services.

Represents secondary school teachers in the Georgian Bay area of Ontario.

Group within OSSTF's District 12 Occasional Teacher's Bargaining Unit advocating democratic reforms within the local.