The rapid growth of mobile technology has transformed how students access information, read, and engage with academic resources. In Nigerian universities, smartphones are increasingly being used for library services, e-learning, and reading activities. However, concerns exist about whether these phones promote or hinder effective library service utilization and reading culture among undergraduates. The study examine the extent of smartphones usage for library services among Nigerian undergraduates, investigate the influence of smartphones on students’ reading culture, and identified challenges associated with smartphone use for academic purposes. The study adopted a mixed research method approach. Questionnaires and focus group discussions were used to gather data, while descriptive statistics and thematic analysis were applied for data analysis. The findings revealed that, while smartphone applications increase access to electronic resources, facilitate online catalogue searches, and support virtual reference services, they also contribute to distraction, reduced attention span, and a preference for social media over academic reading. The study concludes that smartphone play a dual role i.e. enhancing library service utilization while simultaneously eroding deep reading culture. Recommendations include integrating mobile-friendly library platforms, implementing digital literacy training, and encouraging balanced use of smartphone applications to strengthen both academic engagement and sustainable reading culture.