Culicid mosquitoes pose a threat to human and animals due to their capability of disease transmission. In this study, the impact of zinc oxide nanoparticles (ZnONPs) was addressed in the larval stages of Culex mosquito 3 days post treatment. Furthermore, the treated larvae were allowed to recover from the particle-effect for additional 3 and 6 days to address whether the particle impact is sustainable or temporary. To this end, a sub lethal concentration (LC30) of ZnONPs was used to address their impact on the tissues of the alimentary canal and Malpighian tubules of Culex larvae. The treated larvae suffered negative signs on foregut, midgut , hindgut and Malpighian tubule epithelia which appeared in the form of columnar cell vaculation and damage of the microvilli. In the meantime, the larvae which allowed recovering for 3 and 6 days didn’t show signs of improvement in the alimentary canal and Malpighian tubules suggesting sustainable impact of the particles on the larval tissues. Future work will be directed toward ultra-structural studies in the gut cells. This study suggests that ZnONPs can be used as promising tools in controlling mosquito larvae.