The effect of the predatory mite Hypoaspis aculeifer Canestrini (Acarina: Laelapidae) on soil-dwelling stages of the western flower thrips (WFT) Frankliniella occidentalis Pergande (Thysanoptera: Thripidae) and the influence of combined releases of H. aculeifer and two entomopathogenic nematodes (EPNs) Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) (strain HK3, HK3) and Steinernema feltiae Filipjev (Rhabditida: Steinernematidae) (Nemaplus®, SFN) were investigated in pot trials using seedlings of green beans (Phaseolus vulgaris L.). Ten H. aculeifer adults per pot and 400 infective juveniles (IJs) cm−2 soil, of the two EPN strains were used. In comparison with untreated control, H. aculeifer reduced the proportion of adult F. occidentalis emergence by 46%, while SFN and HK3 led to a reduction in adult thrips emergence by 46% and 61%, respectively. Significant differences in adult WFT emergence were found between combined treatments of EPNs and H. aculeifer, and individual applications of EPNs and/or H. aculeifer, with significantly lower adult thrips emergence in the combined treatments. These findings highlight the potential for a combined use of EPNs with H. aculeifer for the control of soil-dwelling stages of thrips.