The Ontario Secondary School Teachers' Federation (OSSTF) is a professional association representing secondary school teachers and educational workers in Ontario, Canada. Established in 1919, it advocates for the rights and interests of its members, focusing on issues such as working conditions, professional development, and educational policy. OSSTF also plays a significant role in collective bargaining, negotiating contracts that cover salaries, benefits, and job security for its members. The federation is committed to promoting quality education and supporting the professional growth of its members through various programs and resources.