The present study focuses on the lethal effect of nine eco-friendly plant-derived essential oils against adult females of Tetranychus urticae Koch under laboratory-controlled conditions. The essential oils of cumin (Cuminum cyminum), thyme (Origanum vulgare), lemon grass (Cymbopogon citratus), clove (Syzygim aromaticum), camphor (Eucalyptus camaldulensis), radish (Raphanus sativus), valerian (Valeriana officinalis), liquorice (Glycyrrhiza glabra) and black pepper (Piper nigrum) were extracted using hydro-distillation Clevenger-type apparatus. Each essential oil was formulated, serially diluted, and in-vitro bioassay using the contact toxicity was assessed one, two, and three days after exposure. Mortality varied according to the essential oil type, time of exposure, and the delivered dose (ppm). Thyme was the most superior potent essential oil against adult females of T. urticae after the three intervals of exposure with LC50 values (18.03, 8.35, and 7.66 ppm), respectively followed by camphor oil, clove oil, and cumin oil. After that the four oils that caused a high percentage of toxicity were sprayed at a concentration of Lc90 on the eggplant plant under greenhouse (in vivo) conditions. The results proved that, all tested oils reduced mite numbers when sprayed by lc90. The reduction percentage for mites' population was 90% by thyme oil, 88% for clove oil, 85% for cumin oil, and 84% for camphor oil. So essential oils proved their ability against T. urticae in vitro and in vivo.