Food insecurity is a mechanism through which the mental health impacts of systemic social inequities multiply across the lifespan. Federally administered food assistance programs improve food security, but their impact on mental health is less clear. We conducted a systematic review of all studies that reported an association between food assistance participation and mental health (N = 34), and a multilevel meta-analysis among studies that met inclusion criteria and reported sufficient statistical results (n = 21; k = 44). The overall effect of food assistance on mental health was not significant (d = -0.025, p = .724). However, follow-up moderator analyses indicated that receipt of food assistance mitigated developmental risk among children (F = 7.73, p = .008). Our results highlight the importance of addressing systemic problems, such as insufficient funds and outdated nutrition guidelines, that limit the potential of food assistance programs to positively affect public health.