Orius sauteri is used as a biological control agent against agricultural pests such as thrips and whiteflies. We investigated the spectral wavelength preference of O. sauteri in a hexagonal arena equipped with six LED lights of different colors: UV (365 nm), violet (405 nm), blue (450 nm), green (525 nm), orange (590 nm), and red (660 nm). Adults were released in the center of the arena and their phototactic behavior toward the LED lights was observed. Approximately 50% of non-mated individuals moved toward the violet light, with no difference between sexes. The spectral preference of males did not change after mating, whereas the preference of females changed dramatically from violet to UV after three days' mating.