This systematic review assesses the relationship between school meals with eating behavior, diet quality, food insecurity, and body mass index (BMI) among Brazilian students. Following PRISMA guidelines, this review was conducted using five databases in March 2023 (Embase, WoS, Medline, Lilacs, Scopus). Database-specific search terms included: "children", "adolescents", "school meals", "Brazilian", "diet", "eating habits", "food insecurity", "body mass index", and synonyms. A total of 26 studies were identified, mostly with BMI/weight status (n=12) or diet/eating habits (n=12) as outcomes. Two studies evaluated the association between school meal consumption and food insecurity (n=2), and showed positive relationship. Most studies showed a positive association of the consumption of school meals with better diet quality and lower consumption of unhealthy foods. More than half of studies about obesity indicators did not show significant results, while two studies found positive and another two negative association. School meals are associated with a healthier diet among students and are serving children from families in vulnerable situations. The effect of school meal consumption on weight status remains unclear.