| Termstart: | 28 October 2020 |
| Office: | Leader of the Opposition |
| Office1: | Member of the National Assembly |
| Termstart1: | 2011 |
| Constituency1: | Proportional list |
| Predecessor: | Wavel Ramkalawan |
| Birth Date: | 26 January 1978 |
| Party: | United Seychelles |
Sebastien Pillay (born 26 January 1978) is a Seychelles politician. He has served as Leader of the Opposition in the National Assembly since 28 October 2020.
Sebastien Pillay was born on 26 January 1978. He received a Bachelor of Education (2004) from Edith Cowan University and a Master of Arts in Educational Leadership & Innovation (2008) from the University of Warwick. Pillay first worked as a mathematics teacher. After receiving promotions within the Department of Education, he then became a Lecturer at the University of Seychelles.[1]
Pillay was first elected to the National Assembly in 2011 on the United Seychelles (then called "People's Party") list. He was re-elected as a list candidate in 2016 and 2020. He was sworn in as the Leader of the Opposition for the Assembly term beginning 28 October 2020.[2]
Pillay was a member of the Electoral Assessment Mission for the 2015 United Kingdom general election.[3]