This paper presents the first finding of Siphonatrophia cupressi (Swain, 1918) (Hemiptera, Aphididae) for Algeria and also for the whole African continent. This aphid pest is reported for the first time from Khenchela Province, North‐Eastern Algeria, on Cupressus sempervirens L. var. horizontalis (Mill.). The first observations were made in a public garden, and other colonies were detected in a nursery producing forest seedlings. Monitoring of these colonies revealed that this aphid is parasitized by Ephedrus persicae Frog and Lysiphlebus testaceipes (Cress.) (Hymenoptera, Braconidae, Aphidiinae).