To examine the mediation effect of discrimination on the association of self-efficacy and oral health behaviours among adolescents. A cross sectional study of adolescents aged 12 to 18 years who were recruited from the University outpatient dental clinic were asked to complete a questionnaire consisting of: demographics (12 items), oral health behaviours (7 items), general self-efficacy (10 items) and self-efficacy for self-care (SESS, 15 items). Perceived discrimination was assessed if the adolescent had ever been treated unfairly based on their race. Perceived discrimination was assessed if the adolescent had ever been treated unfairly based on their race. Using pathway analyses, the relationship between oral health behaviours, self-efficacy, and discrimination was explored. Mediation and hierarchal logistic regression analyses were conducted. Of 252 participants, mean (SD) age was 14 (1.8) years old. 60% were female, 81% were born in Canada, 56% identified themselves as White, and 20% perceived discrimination. Mean score of all task-specific self-efficacies were significantly different within respective oral health behaviour categories (P-value <0.001). Of demographics, age and ethnicity (White) were significantly associated with discrimination (OR = 1.25: 95% CI; 1.06–1.48 and OR = 0.29: 95% CI; 0.15–0.55, respectively). Perceived discrimination was positively associated with higher sugar consumption and mediate the association between diet self-efficacy and adolescent’s dietary behaviour. Significant mediation effect of perceived discrimination on the association of diet specific self-efficacy and diet oral health behaviour was observed. Oral health behaviours were self-reported which may have influenced the results.