The nanocomposite CuO@SiO2 was synthesized through green pathway using Gum Arabic. The green synthesized nanocomposite was characterized using Scanning Electron Microscopy (SEM), Energy Diffraction X-Ray (EDX), Ultra-Violet/Visible spectroscopy, and Fourier Transform Infra-Red (FTIR). These techniques confirmed the formation of CuO@SiO2 nanocomposite. The toxicity studies were conducted for 24 h on 1st, 2nd, 3rd, and 4th instars of malaria vectors at various concentrations of 10, 20, and 25 Mg/L. The LC50 for the 1st, 2nd, 3rd, and 4th instars were found to be 7.525, 7.980, 8.026 and 9.741 Mg/L, respectively, whilst the LC90 for the 1st, 2nd, 3rd and 4th instars were found to be 14.839, 24.937, 57.77 and 48.5 Mg/L, respectively. The correlation coefficient values between concentrations and mortality for instars were obtained in the range of 0.944 - 0.984. These correlation coefficient values indicate that mortality rates increases with the increase in concentrations. The CuO@SiO2 nanocomposite could be a new nanolarvicide for malaria vector control in tropical countries. HIGHLIGHTS Nanocomposite was synthesized through green Sol gel method using gum Arabic and characterized by Scanning Electron Microscopy (SEM), Energy Diffraction X-Ray (EDX), Ultra-Violet/Visible spectroscopy, and Fourier Transform Infra-Red (FTIR) Larvicidal activity of nanocomposite against Anopheles gambiaecomplex was carried following World Health Organization protocol Probit analysis was conducted to evaluate lethal concentrations (LC50 and LC90) of the nanoparticles against the malaria vectors The CuO@SiO2 nanocomposites could be a potential nanolarvicide for larval source management of malaria vectors GRAPHICAL ABSTRACT