John Mastoras

Senior Partner
Norton Rose Fulbright Canada LLP

John Mastoras

John Mastoras



John Mastoras is a senior partner in our Canadian employment and labour law group. He is known to clients as a passionate and dedicated advocate and business partner who provides innovative and practical advice.

John is frequently called upon to litigate highly contentious matters such as disruptive labour disputes and workplace mental health issues, and acts exclusively for employers in the broader area of labour and employment law. He regularly litigates and provides strategic advice in connection with labour arbitrations, labour relations board disputes, human rights proceedings, occupational health and safety charges, workers' compensation, labour injunctions and common law employment actions. His practice spans union and non-union workplaces for both federally and provincially regulated employers.

John is often in the forefront as chief spokesperson in collective bargaining and provides helpful counsel in this regard to a variety of employers. He routinely acts for a broad group of employer clients  and employer associations in various industries and sectors, including energy, pulp and paper, pharmaceutical, healthcare, education, longshoring, construction, retail, food processing, transportation, steel, automotive and manufacturing more generally.

For the past 20 years, John has taught at the University of Toronto's Centre for Industrial Relations and Human Resources (CIRHR), where he is an adjunct professor. In 2009, John was conferred the Morley Gunderson Prize by the University of Toronto as a CIRHR graduate who combines outstanding professional achievement with significant service to the university.

Professional experience

Expand all Collapse all
  • LL.B., Osgoode Hall Law School, 1987
  • M.I.R., University of Toronto, 1984
  • B.A.(Hons.), University of Toronto, 1981
  • Ontario 1989
  • Canadian Legal Lexpert Directory, 2012 - 2021: recommended in Workers' Compensation; 2021: recommended in Occupational Health & Safety; 2016, 2019: recommended in Labour Relations - Management 
  • Acritas Stars, 2021 – Named an Acritas Star
  • Chambers and Partners Canada, Ontario, 2018-2021 – Employment and Labour
  • Best Lawyers in Canada, 2015-2021 – Labour and Employment Law
  • PLC Which lawyer?, 2011 – Labour and Employment
  • University of Toronto, 2009 – Awarded the Morley Gunderson Prize as a CIRHR graduate who combines outstanding professional achievement with significant service to the university
  • "You Can't 'Juke' the Collective Agreement's Exclusive Jurisdiction," Employment and Labour Law Reporter, May 2016 Volume 26, No. 2.
  • "Mexican officials improperly interfered in union representation vote" (co-author), Canadian section, Brussels European Employee Relations Consultants and HR Policy Association, May 2014.
  • "Supreme Court rules random alcohol testing not permitted without evidence of a significant workplace problem" (co-author), Brussels European Employee Relations Consultants and HR Policy Association, February, 2014.
  • "Bill 148: Ready or Not?" Norton Rose Fulbright Annual Workplace Law Conference, May 8, 2018
  • "The Pendulum Swings Left: Bill 148, Fair Workplaces, Better Jobs Act, 2017," Mercer Canada LERN, May 1, 2018
  • "Relationships with Non-Bargaining Unit Employees," Conference Board of Canada, Council of Industrial Relations Executive, June 15, 2017
  • "Dialogue with the Doctor: A Psychiatric Perspective on Workplace Mental Health Issues," Norton Rose Fulbright Annual Workplace Law Conference, May 9, 2017
  • "Ontario's Changing Workplaces Review," Norton Rose Fulbright Annual Workplace Law Conference, May 17, 2016
  • "Representation Elections in Canada – How Does a Speedier Election Process Work in Practice?" U.S. Labor and Employee Relations Network, May 14-15, 2014
  • "Mental Health in the Workplace," CIRA@50 Conference, Ryerson University, May 31, 2013
  • "Navigating the Legal Highway: Recent Labour and Employment Developments," Ontario Trucking Association, February 13, 2008
  • Canadian Bar Association
  • Law Society of Upper Canada
  • The Advocates' Society
  • HR Policy Association (US)  
  • American Bar Association