The mountain was given the name "Sir Thomas" by a team of European explorers in 1891. They were on the Elder Scientific Exploring Expedition, which travelled across the Great Victoria Desert between April 1891 and March 1892. The mountain was named after Sir Thomas Elder, the philanthropist who funded and equipped the expedition. The surrounding range is named after Elder's home in Adelaide, a large house called "Birksgate". Mount Lindsay, to the northeast, was named after the leader of the expedition, David Lindsay.