Tetranychus urticae Koch and T. kanzawai Kishida enter facultative diapause in response to short-day photoperiods. To determine the effect of various colors of light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs) on diapause induction, both species were reared under different photoperiods at 18°C and 2.0 W m^-2 light intensity, in which photon flux density (PFD) was 7.9–11.0 µmol m^-2 s^-1 depending on light quality. Under blue, green, and white LEDs, critical photoperiods were ca. 13.5:10.5 h L: D for T. urticae and ca. 12.5: 11.5 h L: D for T. kanzawai, but no diapause was induced in either species under red LEDs. Under blue, green, orange, and white OLEDs, the critical light phases were ca. 13.3–13.5 h for T. urticae and ca. 12.5 h for T. kanzawai. The inhibitory effects of the duration, quality, and intensity of scotophase-interrupting lights on diapause induction in both species were tested under an 8:16 h L: D photoperiod. In T. urticae females, diapause induction was prevented by interrupting the scotophase with 1 h of light from all colors of LEDs or OLEDs except red LEDs. However, in T. kanzawai females, diapause was fully induced with 1-h scotophase interruption of all light colors and types, even when the PFD was as high as 20 µmol m^-2 s^-1. Interrupting the scotophase with 3 h of 20 µmol m^-2 s^-1 light from blue, green, and white LEDs, and from blue, green, orange, and white OLEDs completely inhibited diapause induction in both species. When interrupting the dark phase with 3 h of light at the lowest intensity tested (0.2 µmol m^-2 s^-1), blue and green inhibited diapause induction in T. urticae, whereas only blue light inhibited diapause induction in T. kanzawai. Therefore, blue LED and OLED performed best to inhibit diapause of T. urticae and T. kanzawai at 3-h scotophase interruption even at low light intensity.