The western conifer seed bug, Leptoglossus occidentalis, is an alien invasive species of North American origin. Leptoglossus occidentalis was recorded for the first time in Arsoun-Metn, Lebanon in 2015. Adults and nymphs of L. occidentalis were collected by the authors from various locations in Lebanon and observed on two species of pine, Pinus pinea and Pinus brutia, on Juniperus excelsa and even on Cedrus libani. This could indicate its successful integration in the country and its presence on many coniferous tree species. Studies to investigate the behaviour and the economic impact of this alien insect species in Lebanon are recommended.