BackgroundThe results of several recent campus-based studies indicate that over half of post-secondary students in Canada are food insecure, but the vulnerability of this group has not been considered in research on predictors of food insecurity in the Canadian population. Our objectives were to (1) compare the prevalence of food insecurity among post-secondary students and non-students of similar age; (2) examine the relationship between student status and food insecurity among young adults while accounting for sociodemographic characteristics; and (3) identify the sociodemographic characteristics associated with food insecurity among post-secondary students.MethodsUsing data from the 2018 Canadian Income Survey, we identified 11,679 young adults aged 19–30 and classified them into full-time postsecondary students, part-time post-secondary students, and non-students. Food insecurity over the past 12 months was assessed with the 10-item Adult Scale from the Household Food Security Survey Module. Multivariable logistic regression analyses were used to estimate the odds of food insecurity by student status while accounting for sociodemographic characteristics, and to identify sociodemographic characteristics predictive of food insecurity among post-secondary students.ResultsThe prevalence of food insecurity was 15.0% among full-time postsecondary students, 16.2% among part-time students, and 19.2% among non-students. After adjusting for sociodemographic factors, full-time postsecondary students had 39% lower odds of being food insecure as compared to non-students (aOR 0.61, 95% CI 0.50–0.76). Among postsecondary students, those with children (aOR 1.93, 95%CI 1.10–3.40), those living in rented accommodation (aOR 1.60, 95%CI 1.08–2.37), and those in families reliant on social assistance (aOR 4.32, 95%CI 1.60-11.69) had higher adjusted odds of food insecurity, but having at least a Bachelor’s degree appeared protective (aOR: 0.63, 95% CI 0.41–0.95). Every $5000 increase in adjusted after-tax family income was also associated with lower adjusted odds of food insecurity (aOR 0.88, 95%CI 0.84–0.92) among post-secondary students.ConclusionsIn this large, population-representative sample, we found that young adults who did not attend post-secondary school were more vulnerable to food insecurity, particularly severe food insecurity, than full-time post-secondary students in Canada. Our results highlight the need for research to identify effective policy interventions to reduce food insecurity among young, working-age adults in general.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12889-023-15756-y.