Academic procrastination remains a common problem among university students, yet most research overlooks discipline-specific dynamics. The purpose of this study was to examine the structural relationships between social media addiction, academic self-efficacy, and academic procrastination among sports science students, with a particular focus on the mediating role of academic self-efficacy. A correlational design and structural equation modeling were conducted with 1,017 sports science students from Turkish universities during the spring semester of 2023 to 2024. Data were collected using validated scales for social media addiction, academic procrastination and academic self-efficacy and analyzed using SPSS and Jamovi. Results showed that social media addiction positively predicted academic procrastination, while academic self-efficacy negatively predicted both social media addiction and academic procrastination. Importantly, academic self-efficacy significantly mediated the relationship between social media addiction and academic procrastination, accounting for approximately 41% of the indirect effect. The direct effect of social media addiction on academic procrastination remained significant and together social media addiction and academic self-efficacy explained 55% of the variance in academic procrastination. These results emphasize the crucial role of academic self-efficacy in buffering the negative impact of social media addiction on procrastination among sports science students. Considering the cross-sectional design and the fact that the study was based on self-report, future research should use longitudinal studies and mixed methods to confirm these findings and improve generalizability. In general, the study emphasizes the need for targeted educational interventions to strengthen academic self-efficacy and reduce procrastination, especially among digitally engaged student groups.