The Prix Iris for Best Costume Design () is an annual film award, presented by Québec Cinéma as part of its Prix Iris awards program, to honour the year's best costume design in films made within the Cinema of Quebec.
The award was presented for the first time at the 6th Jutra Awards in 2004.
Until 2016, it was known as the Jutra Award for Best Costume Design in memory of influential Quebec film director Claude Jutra. Following the withdrawal of Jutra's name from the award, the 2016 award was presented under the name Québec Cinéma. The Prix Iris name was announced in October 2016.
Ginette Magny received the most nominations, ten, while Carmen Alie and Francesca Chamberland won the most awards, with three each, including consecutive wins: in 2013 and 2014 for Alie and in 2021 and 2022 for Chamberland. Xavier Dolan is the only costume designer to receive a nomination for a film he also directed with Mommy.