The zoophytophagous mirid Nesidiocoris tenuis (Hemiptera: Miridae) is one of the biological control agents against the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae), a major pest of greenhouse crops. The successful establishment of a biological control agent and its co-occurrence with the target pests increases the efficacy of biological control programs in greenhouses. In this study, we explored the effects of different wavelengths of LED light on establishment of N. tenuis in laboratory condition, with the goal of enhancing the biological control of B. tabaci in greenhouse crops. Nesidiocoris tenuis was most strongly attracted by LED light at a wavelength of 385 nm. This same wavelength was also highly attractive to B. tabaci in Y-tube experiments with lights of specific wavelengths provided is each arm of the apparatus. In trials in growth chambers, we verified the attraction of N. tenuis to 385 nm wavelength. When LED light at a wavelength of 385 nm was used in a growth chamber for 6 hours out of 24 hours, it significantly increased the remaining number of N. tenuis in growth chamber and level of predation compared to treatment with white LED light or without LED light. In conclusion, UV-LED light at a wavelength of 385 nm attracts both B. tabaci and N. tenuis. Thus, it would be used for enhancing early establishment of this mirid bug, better spatial congruence of both mirid bug and whitefly, and better control of the whitefly.