T HE mosquitoes Culex pipiens are important vectors for transmitting Rift Valley fever and lymphatic filariasis in Egypt. Plant essential oils (EOs) are one of the most promising larvicides. This study assessed the larvicidal efficacy of 15 EOs of which two were new against fourth larval instars of Cx. pipiens. Five concentrations (125, 250, 500, 1,000, and 2,000 ppm) were used for each oil. Mortalities (MOs) were monitored 24 hours post-treatment. After treatment with 2000 ppm for 24 hours, EOs were classified into three groups. The highly effective group provided eight EOs ranging from 91 to 100% MO includingRicinus communis, Pimpinella anisum, Matricaria chamomilla, Vitis vinifera, Allium sativum, Jasminum sambac, Cinnamomum verum, and Rosmarinus officinalis. Their lethal concentrations (LC 50 ) ranged from 454.48 ppm (R. communis) to 754.30 ppm(C. verum). The moderately effective group resulted in 90% MO by Trigonella foenum-graecum, Simmondsia chinensis, Brassica compestris, and Carum Petroselinum. The LC 50 values varied from 823.84 ppm (C. petroselinum)to 1,120.91 ppm (S. chinensis). The least effective group provided less than 90% mortality and included Cocos nucifera, Zingiber officinale, and Lavandula angustifolia.C. nucifera andJ. sambac were novelty used against Cx. pipiens. R. communis, and M. chamomilla were recommended for field application as eco-friendly larvicides.