Sébastien Viars (born 24 June 1971) is a former French rugby union footballer.
He won the Heineken Cup, in 1997, with CA Brive, scoring an anthological try in the 28–9 win over Leicester Tigers, from England.
Viars held 17 caps for France, from 1992 to 1997, scoring 9 tries, 17 penalties and 17 conversions, 127 points in aggregate.
He played two times at the Five Nations, in 1992 and 1995, scoring 4 tries, 6 conversions and 4 penalties, 41 points in aggregate.
Viars was selected for the 1995 Rugby World Cup finals, playing a single game, in the 54–18 win over Côte d'Ivoire and scoring a try.