This study investigated the conceptions of the nature of science held by pre-service undergraduate biology teachers in South-West, Nigeria. Specifically, the study examined the influence of their gender on their conceptions of the nature of science. The study was a descriptive research of the survey method. The population for the study comprised all undergraduate pre-service biology teachers in Nigerian universities. Stratified random sampling technique was used to select ninety nine (99) undergraduate pre-service biology teachers from three universities in South-West, Nigeria. The nature of science questionnaire (NoSQ) was used to collect data. Results revealed that pre-service undergraduate teachers' gender did not influence their conceptions. It was recommended that biology teacher educators should equip the pre-service undergraduate biology teachers with meta-cognitive tools such as Study Technology to enable them to learn for meaningful understanding.