Sébastien de Chaunac (born 7 October 1977) is a retired French professional tennis player.

Prior to turning pro, de Chaunac played three collegiate seasons (1995–98) at the University of Mississippi and was tabbed an All-American in his final two years.

An all-SEC selection in his final two seasons, he helped the Rebels claim SEC regular-season titles in both 1996 and '97, as well as the tournament crown in the latter year.

An outstanding student, de Chaunac was named to the GTE/CoSIDA Academic All-America First Team in 1998 and had a perfect 4.0 grade-point average.

He beat Gary Lugassy (6–4, 6–3), Alex Bogdanović (6–3, 6–2) and Santiago Ventura (6–4, 6–1) to qualify for the main draw of the Australian Open for the second time in his career after a first round appearance in 2004.

In the first round, he upset third seed Marcel Granollers 7–5, 7–6(3) then defeated local wildcard Izak van der Merwe in a hard-fought 6–7(3), 7–5, 7–6(5) victory to reach the quarter-finals of an ATP tournament for the first time since February 2005 in Marseille.

This period was highlighted only by a semifinal run at the Jersey Challenger in March and a final at a Futures tournament in Newcastle upon Tyne in May.