Mosquitoes are important vectors of diseases that pose major public health challenges. This study investigated the prevalence and distribution of Aedes and Culex species within Ajayi Crowther University, Oyo State, Nigeria. Larvae were collected from ten randomly selected sites over a five-month period (November–March). A total of 10,033 mosquitoes were recorded, comprising Culex spp. (5,141; 53.8%) and Aedes spp. (4,892; 46.2%). Statistical analysis showed significant variation across months (p = 0.005) and locations (p = 0.002), while no significant interaction was observed (p = 0.074). The predominance of Culex highlights the risk of diseases such as lymphatic filariasis and West Nile virus, whereas Aedes remains relevant for dengue, yellow fever, and chikungunya transmission. These findings provide baseline data for vector control programs in Atiba Local Government and contribute to understanding mosquito distribution in Oyo State.