Medical students are at an increased risk for burnout compared to the general population (Dyrbye et al., 2014). Research has identified certain demographics as predictors of burnout in medical students (Cecil et al., 2014; Dyrbye et al., 2007; Dyrbye & Shanafelt, 2016), but most research has not examined a combination of demographic variables in one model. Moreover, physical activity (PA) and sedentary behaviour are two modifiable risk factors for burnout (Naczenski et al., 2017; Sloan et al., 2013). However, less is known about how PA intensities and sedentary behaviour influence burnout in medical students. This research investigated how demographics (gender, ethnicity, age, level of education, year of study, proposed specialty) and health behaviours (mild, moderate, and vigorous PA, and sitting) predicted burnout in medical students. Medical students (N=129) completed surveys of validated questionnaires assessing demographics, PA, sitting, and burnout. Data were analysed using multivariate linear regression. Results showed that female gender (?=.221, p=.016), 'other' ethnicity (?=.185, p=.040), third year (?=.435, p=<.001), and fourth year (?=.229, p=.029) were significant positive predictors of burnout. Approaching significance, the regression also showed that mild PA was a negative predictor (?=-.159, p=.071) and moderate PA was a positive predictor (?=.155, p=.092) of burnout. These results suggest certain medical students may be more at-risk for burnout and should be targeted in interventions and that burnout may be prevented by engaging in mild versus moderate PA. This knowledge fills many gaps in the literature and can inform medical stakeholders in developing targeted programs for our future physicians.