Abstract Objective: To examine the associations between food insecurity (IA) and social support in families of children with sickle-cell disease (DF). Methods: This cross-sectional study in families of 190 children from five to nine years old in follow-up at a hematology referral hospital in Rio de Janeiro State. IA was measured using the Brazilian food insecurity scale and social support was measured using the Brazilian version of the MOS social support survey instrument. The relation between IA and social support was analyzed by way of a multinomial logistic model. Results: There was IA in 62.2% of the families, in moderate and severe form in, respectively, 11.1% and 7.9% of cases. In families of children with DF, levels of mild and severe food insecurity (IALe and IAGr) were found to relate inversely to levels of social support in the following dimensions: informational support (IALe OR = 0.98; 95% CI 0.96–0.99 and IAGr OR = 0.95; 95% CI 0.92–0.98); social interaction (IALe OR = 0.98; 95% CI 0.96–0.99 and IAGr OR = 0.96; 95% CI 0.93–0.99) and tangible social support (IALe OR = 0.97; 95% CI 0.96–0.99 and IAGr OR = 0.97; 95% CI 0.94–0.99). Conclusion: Considering the positive effects of social support on IA, public policies should be encouraged to assure food and nutritional security and social assistance for care for people with DF. Also, social support groups for people with DF should be strengthened.