Background: Early life socioeconomic disadvantage and adverse experiences maylead to overeating, which is in turn associated with increased body mass index (BMI).However, recent evidence indicated that the association between childhood BMI andovereating might be bidirectional. This bidirectionality prompts the need for furtherinvestigation of early life predictors of BMI in childhood.Objectives: To longitudinally assess the directionality of the association betweenchildhood BMI and perceived overeating and to investigate their antecedent early lifepredictors.Methods: The sample included data from 5151 children from the ELSPAC study, col-lected between 18 months and 11 years of child age. The outcomes were child BMIand mother-reported overeating, assessed at the age of 3, 5, 7 and 11 years. Predic-tors included maternal BMI, maternal education, single parenthood, financial difficul-ties and adverse childhood experiences (ACEs) reported by parents andpaediatricians. The random intercept cross-lagged panel model was applied.Results: The mean child's BMI at age 3 was 15.59 kg/m 2 and increased to 17.86 kg/m2 at age 11. The percentage of parent-reported overeating increased in the follow-ing period, from about 12% at age 3 to 17% at age 11. The results showed temporalstability in perceived overeating and BMI, with a bidirectional relationship strength-ening over time. The child's BMI was associated with maternal BMI. Maternal BMIwas positively associated with child-perceived overeating, but a stronger effect wasfound for ACEs. ACEs mediated the impact of maternal education, financial difficul-ties and single parenthood on overeating.Conclusions: We observed stable bidirectional associations between BMI and per-ceived overeating. The results indicated two main pathways: one linked to maternalBMI and early childhood BMI increase followed by perceived overeating and the sec-ond associated with ACEs mediating the effect of early childhood social factors onperceived overeating, leading to gradual BMI gain.