Valentin André Henri Rosier (born 19 August 1996) is a French professional footballer who plays as a right-back for CD Leganés.

Born in Montauban, Tarn-et-Garonne, of Guadeloupean, Malagasy and Italian descent,[3] Rosier began his senior career with Rodez AF in the fourth tier in 2015, moving to Dijon FCO of Ligue 1 a year later, on a three-season contract.

[5] On 27 June 2019, Rosier signed a three-year contract at Sporting CP of Portugal's Primeira Liga, for a fee of €7.5 million and the exchange of Mama Baldé to Dijon.

[9] On 11 December 2023, it was officially announced that Rosier has been excluded from the squad along with Vincent Aboubakar, Eric Bailly, Rachid Ghezzal and Jean Onana due to poor performance and incompatibility within the team.

[11] On 4 July 2024, Rosier joined newly promoted Spanish La Liga club CD Leganés on a four-year deal.