Regular physical activity as an important health promotion behavior has many results in prevention or delay of chronic diseases and premature death. The aim of this study was to establish the determinants associated with regular physical activity among college students based on social cognitive theory (SCT). This study was a cross-sectional study carried out among 212 students in Abadan school of medical sciences, in the south west of Iran, during 2016. Data collection was self-report questionnaire in four parts including: demographic information, constructs of SCT, and standard international physical activity questionnaire-short form (IPAQ), social support. Data were analyzed by SPSS-16, and by using bivariate correlations and logistic regression at 95% significant level. About 61.7% (108/175) had low, 33.7 (59/175) moderate, and 4.6% (8/175) vigorous physical activity. Outcome expectation (OR=1.710), self-efficacy (OR=1.523), and friends' support (OR=1.149) was the best predictor for regular physical activity. It seems the planning and implementation of programs for physical activity promotion among college students is essential by emphasising on outcome expectation, selfefficacy, and social support.