In this study, we describe Ambulyx labuanensis sp. nov., a new hawk moth species from Flores Island (East Nusa Tenggara, Indonesia). This species is morphologically similar to Ambulyx moorei Moore, 1858, A. amboynensis Rothschild, 1894, A. bakeri (Clark, 1929), A. celebensis (Jordan, 1919), A. dohertyi Rothschild, 1894, and A. semifervens (Walker, 1865). However, it clearly differs from these species by having two large saccular processes on the valva.