ObjectiveEducation is a crucial social determinant of health. Food insecurity can be detrimental to children’s academic achievement, potentially perpetuating a cycle of poverty and food insecurity. We aimed to assess the relationship between food insecurity and academic achievement in Canadian school-aged children.DesignCross-sectional study of children and parents. Parents completed the short-form Household Food Security Survey Module and questions about income and education level (socio-economic status). Children completed FFQ. Data were prospectively linked to children’s performance on standardized exams written one year later. Mixed-effect logistic regression was employed to assess the relationship between food insecurity and likelihood of meeting academic expectations adjusting for socio-economic status, diet quality and potential confounders.SettingNova Scotia, Canada in 2011–2012.SubjectsStudents (n4105) in grade 5 (10–11 years; 2167 girls) and their parents.ResultsLow food security was reported by 9·8 % of households; very low food security by 7·1 % of households. Students from low-income households and reporting poor diet quality were less likely to do well in school. Children who lived in households reporting very low food security had 0·65 times the odds (OR=0·65; 95 % CI 0·44, 0·96) of meeting expectations for reading and 0·62 times the odds (OR=0·62; 95 % CI 0·45, 0·86) of meeting expectations for mathematics.ConclusionsVery low household insecurity is associated with poor academic achievement among children in Nova Scotia.