Karl Thorsten Gunnar Andersson (23 February 1929 – 4 April 2018) was a Swedish toponymist, and a former Professor of Linguistics at Uppsala University.

Karl Thorsten Gunnar Andersson was born in Ödeshög Municipality, Sweden on 23 February 1929.

Andersson received his PhD from Uppsala University in 1965, where he subsequently became a docent in Nordic languages.

From 1971 to 1994, Andersson was Professor of Linguistics at Uppsala University.

He was the publisher of Namn och bygd and co-publisher of Studia Anthroponymica Scandinavica.