Thomas Stewart is an Associate Professor of Linguistics in the Department of Comparative Humanities. He joined the University of Louisville in 2009.

His research focuses on linguistic theory, particularly on morphology and its interfaces, and also on language contact and change. His primary research language is Scottish Gaelic. He is currently working on Morphology Unchained, a book about types and systems of word-marking other than prefixes and suffixes. He is the series editor for Cambridge Elements in Morphology.