Self-regulation is widely recognized as a key competency supporting students' learning, character development, and long-term educational success. Within Islamic boarding schools, voluntary religious practices may provide repeated opportunities for students to strengthen self-regulatory capacities through everyday behavioral discipline. However, empirical evidence examining voluntary sunnah fasting from an educational psychology perspective remains limited. This study investigated the associations between voluntary sunnah fasting, patience, and delayed gratification among students in an Islamic boarding school. A quantitative cross-sectional design was employed involving 60 students selected through purposive sampling. Data were collected using self-report questionnaires and analyzed using descriptive statistics, Pearson's correlation, and simple linear regression. The findings indicated that voluntary sunnah fasting was positively associated with patience (β = .529, p < .001) and delayed gratification (β = .535, p < .001). Regression analyses further showed that voluntary sunnah fasting significantly predicted patience (R² = .280) and delayed gratification (R² = .286). These findings suggest that students who more consistently engage in voluntary sunnah fasting tend to demonstrate stronger emotional regulation and greater capacity to delay immediate rewards in pursuit of longer-term goals. The study contributes to educational psychology by positioning voluntary sunnah fasting as a behavioral practice that may support students' self-regulation and character development within Islamic boarding school education. Future research employing longitudinal and intervention-based designs is recommended to examine the educational implications of these relationships across broader learning contexts.