Language attitudes have become more pertinent than ever as a result of the great number of immigrant students enrolled in the Catalan educational system and the challenges this involves in terms of fostering social integration and language learning. Thus, the aim of this inquiry is to enhance our grasp of language attitudes formation by assaying how origin (autochthonous or immigrant) affects (a) the attitudes towards Catalan and Spanish and (b) the impact of diverse sociopsychological and demographic variables on these attitudes. Additionally, it sets out to distinguish the most notable determinants of these language attitudes. For this purpose, 1156 secondary education students from 10 schools across Catalonia completed a language attitudes questionnaire, a sociolinguistic survey, and two language competences tests. The results displayed that, generally, self-identifications and language uses were the most weighty. Furthermore, origin mitigated the links between attitudes and their determinants, pointing out that the models traditionally employed to clarify the attitudes held by autochthonous students need to be reconsidered to take into account the peculiarities of the immigrant population.