List of winners and nominees of the César Award for Best Supporting Actor.

The 49th César Awards ceremony, presented by the Académie des Arts et Techniques du Cinéma, took place on 23 February 2024 at the Olympia in Paris, to honour the best French films of 2023. Valérie Lemercier presided over the ceremony, after serving as the host for three previous editions. Mirroring the previous ceremony, multiple actors and filmmakers hosted the 49th iteration: Ariane Ascaride, Bérénice Bejo, Dali Benssalah, Juliette Binoche, Dany Boon, Bastien Bouillon, Audrey Diwan, Ana Girardot, Diane Kruger, Benoît Magimel, Paul Mirabel, Nadia Tereszkiewicz and Jean-Pascal Zadi.