Ontario Secondary School Teachers' Federation
| Abbreviation | OSSTF |
|---|---|
| Formation | 1919 |
| Type | Trade union |
| Headquarters | Toronto, Ontario, Canada |
| Location |
|
| Membership | 60,000 |
President | Karen Littlewood |
| Affiliations | |
| Website | osstf |
The Ontario Secondary School Teachers' Federation (OSSTF) is a Canadian trade union which represents 60,000 members across Ontario.
Founded in 1919, its membership includes public high school teachers, occasional teachers, teaching assistants, psychoeducational consultants, social workers, child and youth counsellors, speech-language pathologists, continuing education teachers, early childhood educators, instructors, and support staff from several Ontario universities.