Leo Groarke (born 1953) is a Canadian philosopher, known for his contributions to argumentation theory and informal logic.

Groarke has authored and edited a number of books, articles, and anthologies.^[1] Groarke has held numerous administrative positions at various Canadian universities, and currently serves as the President of Trent University.^[2]

He is the brother of philosophers Louis Groarke and Paul Groarke. The three are identical triplets.^[3]

Groarke studied at the University of Calgary, Simon Fraser University, the University of Helsinki, and the University of Western Ontario. He earned his PhD in philosophy in 1982 and was a professor of philosophy at Wilfrid Laurier University, also holding several administrative positions. From 2010 to 2015 he served as the provost/vice-president academic at the University of Windsor.^[1] Since 2014 he has been the president of Trent University.^[2]

Groarke's publications have concerned Ancient Greek philosophy, the history of ideas, and argumentation theory. He has published several papers on the possibility of arguments in non-linguistic modes, such as visual and musical arguments. With David Birdsell, he edited a special edition of Argumentation and Advocacy on Visual Argumentation in 2007.^[1] He is the author of the Stanford Encyclopedia of Philosophy entry for Informal Logic, and also wrote the 2008 edition of the Stanford Encyclopedia entry for Ancient Skepticism.^[4][5]

• Good Reasoning Matters! Revised 4th Ed. with Christopher Tindale (Toronto: Oxford University Press, 2008)
• Greek Scepticism: Anti-Realist Trends in Ancient Thought (Kingston, Montreal: McGill-Queen's University Press, 1990)