Mosquito-transmitted diseases, including chikungunya, malaria, dengue, chikungunya, Zika virus disease, and yellow fever remain major global public health threats, especially in tropical and subtropical regions. This challenge has encouraged the search for eco-friendly and sustainable alternatives pesticides, particularly plant-based compounds with repellent and larvicidal properties. The current study aimed to evaluate the larvicidal activity of Bougainvillea glabra extract against third larval instars Culex pipiens Linnaeus (Order: Diptera, Family: Culicidae) under controlled laboratory conditions. Larvae were subjected to different concentrations of the methanolic extract of Bougainvillea glabra (40, 80, 120, 160, 200 μg/mL) for 36 hours. Results showed a clear concentration-dependent effect, with mortality rates ranging from 40% to 100%. The methanol extract exhibited strong toxicity, with LC50 and LC90 values of 69.01 μg/mL and 174.57 μg/mL, respectively. These findings indicate that Bougainvillea glabra extract has significant larvicidal potential and may serve as an effective, natural alternative for mosquito control strategies.