Part-time professors at the University of Ottawa are now on strike after their union and employer failed to negotiate the terms of a new collective agreement. The Association of Teaching Professors at the University of Ottawa (ATPUO) says the strike began at midnight on Saturday with picketing activities expected to begin Monday. In a statement, uOttawa says the school remains open during the strike and is working to minimize the impact to students. “We understand that this disruption creates uncertainty and concern, especially for students working to complete their courses and continue their academic journeys,” uOttawa said in a statement on its website. “The university regrets the disruption and the stress this may cause. The university community’s continued patience, understanding and support are appreciated during this time.” Many courses taught by part-time professors will be suspended during the strike, but most co-op, internships, practicums and experiential learning activities are not impacted. Labs and discussion groups that are under the supervision of a teaching assistance or lab technician are not affected by the strike. The ATPUO represents approximately 2,500 teaching professors who teach more than half of the courses at the university, according to the union. In the fall of 2025, uOttawa employed 1,143 part-time professors, including part-time language teachers. In September, ATPUO members voted in favour of job action, including 88.2 per cent of the members of its main unit, 73.1 per cent from the Official Languages and Bilingualism Institute (OLBI) and 100 per cent of the Toronto-Windsor unit. The union says it is seeking proposals aimed at improving job security and protections for its members. It recently expressed concerns about the university rolling back protections against sexual harassment, increasing class sizes, threats posed by artificial intelligence, and exclusion of its members from decision-making bodies, including the Board of Governors. “The employer’s latest proposal is extremely disappointing. In our view, it does not allow the parties to make significant progress toward a fair and equitable settlement. At this stage of the bargaining process, we hope for a stronger commitment from the employer,” the union said in its latest bargaining update. The university says it remains committed to reaching a fair agreement. “Our part-time professors are valued members of our community. They play an essential role in the learning experience of our students and in the life of our university,” the university said.