Koceila Julien Mammeri (born 23 February 1999) is a badminton player from Algeria who trained at the Oullins club in France. In the junior event, he was the third place at the Portugal International tournament in the boys' doubles event. He won gold medals at the 2017, 2019, 2020, 2021 and 2022 African Championships for men's doubles with his partner Youcef Sabri Medel, and in 2018 and 2019 for mixed doubles with Linda Mazri, and also in 2021 and 2022 for mixed doubles with . Together with Mazri, he claimed the gold medal at the 2019 African Games.