In this study we compare the distribution of parental educational styles and the scores reported both by parents and students for various family characteristics (acceptance, control, involvement, and expectations) and socio-demographic factors (socio-economic status, family structure, number of children, and order of birth of the children) in a group of adolescents with normal achievement (n = 105) and in a group which present low achievement (n = 205). Likewise, we examine which variables best predict academic achievement in the two groups and of adolescents. The results indicate differences in the distribution of parental styles in the two groups for the majority of the variables analysed. We also observed a differential pattern in the prediction of academic success. In the group of adolescents with normal academic achievement, socio-demographic variables better predict achievement; for students with low achievement, family variables play a more important role in predicting achievement.