This study investigates the relationship between social media usage and academic motivation among university students, with sleep quality examined as a potential mediator. A total of 384 undergraduate students (162 males, 222 females) aged 18–24 years (M = 20.21, SD = 1.62) from four engineering colleges in India participated. Data were collected using the Social Media Use Integration Scale (SMUIS), Pittsburgh Sleep Quality Index (PSQI), and Academic Motivation Scale (AMS). Pearson correlations, independent t-tests, and mediation analysis using Hayes’ PROCESS macro (Model 4) were conducted. Results indicated that high social media usage was significantly associated with poorer sleep quality and lower academic motivation. Sleep quality significantly mediated the relationship, accounting for 19% of the variance in academic motivation. These findings highlight the importance of promoting healthy digital habits and sleep hygiene to support academic engagement.