Objective: Test the hypothesis that smoking, fast-food consumption, and binge drinking were negatively associated with academic performance in Canadian undergraduate students. Participants: Undergraduate students across Canada [n = 411 (335[female gender symbol]) aged: 22 ± 4 years] completed a questionnaire regarding their lifestyle behaviors and academic grades. Methods: Relationships between lifestyle behaviors and academic performance were assessed via covariate-adjusted multiple regressions. Mediation models were used to test whether significant relationships between smoking/fast-food and grades were explained by binge drinking. Results: Smoking ([beta]= -4.00, p < 0.001) and binge drinking ([beta]= -1.98, p = 0.002) were independent predictors of grades (average: 84 ± 8%). Binge drinking partially mediated the relationships between smoking (indirect effect [beta]= -1.19, 95%CI [-2.49, -0.08] and fast-food consumption (indirect effect: [beta]= -0.75, 95%CI [-1.20, -0.29]), with grades. Conclusions: These findings highlight the negative influence of binge drinking, smoking, and fast-food consumption on academic success, with binge drinking as a partial mediator of these relationships.