Lake Thomas () is a meltwater lake that is circumscribed on the northwest and northeast sides by Robertson Ridge and Clark Glacier, in Victoria Land. Named by Advisory Committee on Antarctic Names (US-ACAN) for Robert H. Thomas who participated in United States Antarctic Research Program (USARP) studies of the surface glaciology of the Ross Ice Shelf in the 1973-74 and 1974-75 seasons.
This article incorporates public domain material from the United States Geological Survey document "Lake Thomas" (content from the Geographic Names Information System).