Sebastian Fanselow (born 30 December 1991) is a German tennis player. He has a career high ATP singles ranking of world No. 273 achieved on 8 August 2022, and a doubles ranking of No. 358 achieved on 15 August 2022.
He made his ATP main draw debut at the 2024 Lyon Open after entering the singles main draw as a lucky loser, losing to Yoshihito Nishioka in the first round.