This study aimed to determine the trends of smartphone usage and behaviours associated with its use among undergraduate medical students at ABWA Medical College, Pakistan. Conducted from July to December 2023, this cross-sectional survey involved 270 undergraduate medical students, with 264 participants responding, resulting in a 97.7% response rate. The validated Smartphone Addiction Survey (SAS) was administered via an online Google form after obtaining informed consent. Data was analyzed using SPSS version 25.0. The study identified that smartphone usage among medical students includes information storage, communication, education, and entertainment, with no statistically significant gender-based differences (p > 0.05). Behaviours associated with smartphone usage included daily life disturbance, overuse, withdrawal, cyberspace-oriented relations, and tolerance. The ANOVA test revealed significant differences in cyberspace-oriented relations (p = 0.012), while no significant differences were found among different MBBS classes for daily life disturbance, overuse, withdrawal, and tolerance. These findings provide valuable insights into smartphone usage patterns and behaviours among medical students, highlighting significant variations in online interaction habits. The results can inform targeted interventions to promote healthy smartphone use and improve educational experiences for medical students in the digital age.