Socioeconomic factors at both contextual and individual levels influence health.Evaluate the influence of socioeconomic inequalities on the incidence of dental caries in adolescents.This cohort study was conducted with a multistage random sample of 1,134 12-year-old adolescents from Southern Brazil. The experience of dental caries was assessed according to the decayed, missed, or filled surfaces (DMF-S) index. The Basic Education Development Index (IDEB) was collected during baseline as a school-level variable. Individual variables included demographic, socioeconomic, behavior-related, and oral health measures. Multilevel Poisson regression analysis through a hierarchical approach was used to explore the influence of exploratory variables on the mean of decayed surfaces.770 14-year-old adolescents were reevaluated (follow-up rate of 68%) after two years. Examiner´s Kappa values for the assessment of dental caries ranged from 0.81 to 0.90. Adolescents with low household income and lower school's IDEB had higher mean of decayed surfaces. Non-white adolescents, lower frequency of dental attendance, parents' poor perception of child's oral health, and dental plaque were also associated with the incidence of dental caries.Adolescents from a lower socioeconomic background and poor school context had higher levels of dental caries over time. This article is protected by copyright. All rights reserved.