David G. Duff is Professor of Law and Director of the Tax LLM program at the Peter A. Allard School of Law at the University of British Columbia, where he teaches and writes in the areas of areas of tax law and policy, corporate and international taxation, environmental taxation and distributive justice. 

Prior to joining UBC Law in 2009, Professor Duff was a faculty member of the University of Toronto Faculty of Law. Before that, he was a tax associate at the Toronto office of Stikeman, Elliott. He was also employed as a researcher with the Ontario Fair Tax Commission from 1991 to 1993 and as a tax policy analyst with the Ontario Ministry of Finance from 1993 to 1994.

He is a member and former Governor of the Canadian Tax Foundation, a member of the International Fiscal Association and the governing council of the Canadian branch of the International Fiscal Association, and an International Research Fellow of the Oxford University Centre for Business Taxation, and has been a visiting scholar at the Max Planck Institute for Public Finance and Tax, the Oxford University Centre for Business Taxation, and the law faculties at Auckland University, Hebrew University in Jerusalem, McGill University, the University of Ottawa, Oxford University, and the University of Sydney. 

Professor Duff has published numerous articles on tax law and policy, is the primary author Canadian Income Tax Law (5th ed., 2015) and The Taxation of Business Organizations in Canada (2015), and has co-edited books on tax avoidance in Canada, Canadian climate change policy, and environmental taxation. He has written several articles on tax avoidance and the interpretation of tax legislation and tax treaties, and was cited ext4ensively by the Supreme Court of Canada in its decision on the Canadian General Anti-Avoidance Rule (GAAR) in Copthorne Holdings Ltd. v. Canada, 2011 SCC 63.