Yahatanishi-ku (八幡西区) is a ward of Kitakyūshū, Fukuoka, Japan. It covers 83.04 square kilometres, and had a population of 260,318 in January, 2005. The ward contains JR Kurosaki Station, and JR Orio Station on the Kagoshima Main Line, with several schools and universities nearby. It is chiefly a residential area, bounded by the Onga river in the West.