EnglishThe main goal of this research was the analysis of the psychometric proprieties of a self -concept and self-esteem scale and the study of the self-concept organizational structure in pre-adolescents. Participants were 774 Portuguese students attending 5th and 6th grades. The scale used assesses seven specific dimensions of self-concept (school competence, athletic competence, social acceptance, physical appearance, native language competence, mathematics competence, behavior), as well as self-esteem. Confirmatory factor analyses supported the multidimensionality of self-concept, and a bi-factor model with two global factors (academic self-concept and non-academic self-concept) was the one that presented a better fit. This model enables to integrate structural characteristics of self-concept that seemed to be incompatible in previous research. portuguesEste estudo teve como objetivo a analise das propriedades psicometricas de uma escala de autoconceito e autoestima e da estrutura organizativa do autoconceito em pre- adolescentes. Participaram 774 estudantes Portugueses do 5o e 6o anos de escolaridade, que responderam a uma escala que avalia sete dimensoes especificas do autoconceito (competencia escolar, competencia atletica, aceitacao social, aparencia fisica, competencia a lingua materna, competencia a matematica, comportamento) e a autoestima. As analises fatoriais confirmatorias demonstraram a multidimensionalidade do autoconceito sendo o modelo bi-fatorial com dois fatores globais (autoconceito academico e nao academico) aquele que apresentou um melhor ajustamento aos dados. Este modelo tem a vantagem de integrar caracteristicas estruturais do autoconceito que em estudos anteriores foram consideradas incompativeis.