Food insecurity is a pervasive public health problem in high income countries, disproportionately affecting households with children. Though it has been strongly linked with socioeconomic status and investments in social protection programs, less is known about its sensitivity to specific policy interventions, particularly among families. We implemented a difference-in-difference (DID) design to assess whether Canadian households with children experienced reductions in food insecurity compared to those without following the roll-out of a new country-wide income transfer program: the Canada Child Benefit (CCB). Data were derived from the 2015-2018 cycles of Canadian Community Health Survey. We used multinomial logistic regressions to test the association between CCB and food insecurity among three samples: households reporting any income (N = 41,455), the median income or less (N = 18,191) and the Low Income Measure (LIM) or less (N = 7579). The prevalence and severity of food insecurity increased with economic vulnerability, and were both consistently higher among households with children. However, they also experienced significantly greater drops in the likelihood of experiencing severe food insecurity following CCB; most dramatically among those reporting the LIM or less (DID: -4.7%, 95% CI: -8.6, -0.7). These results suggest that CCB disproportionately benefited families most susceptible to food insecurity. Furthermore, our findings also indicate that food insecurity may be impacted by even modest changes to economic circumstance, speaking to the potential of income transfers to help people meet their basic needs.