Library is considered as an important input needed to implement school programs. In the light of the foregoing, this study examined the perceived influence of library services on students’ academic achievement in secondary schools. Non-probability techniques (stratified, purposive and convenience sampling techniques) were used to select 20 schools and its principals from three senatorial districts in Kwara State. The research design used combined both interview and observational checklist to collect relevant data for the study. Nvivo software (version 10) was used to analyse the data collected. Findings of the study revealed that library services positively influenced students’ academic achievement. Findings also showed that schools lacked adequate library facilities and materials. Non/Inadequate trained library personnel were also found in schools. The study recommends that government at all levels (federal, state and local) in collaboration with other stakeholders in education, should build modern libraries in public secondary schools in the state and equip them with all necessary library facilities, while private secondary schools should be mandated to do so. Lastly, there is need for collective action by individuals and Non-Government Organizations (NGOs) to contribute to the development of school libraries in the state.