This inquiry aims at enhancing our grasp of language attitudes formation by exploring how origin (autochthonous or immigrant) affects (a) the attitudes towards Catalan and Spanish and (b) the effects of various demographic and sociopsychological variables on these attitudes. It sets out to distinguish the most notable determinants of these language attitudes as well. For this purpose, 1156 secondary education students from 10 schools across Catalonia completed a language attitudes questionnaire, two language competences tests and a sociolinguistic survey. The results displayed that, generally, self-identifications and language uses were the most weighty. Furthermore, origin mitigated the relationships between attitudes and their determinants, pointing out that the models traditionally employed to account for the attitudes held by autochthonous students need to be reviewed to reckon with the peculiarities of the immigrant population.