PaperImmigrants, Language Attitudes, Multilingualism, Catalonia Language attitudes have become more relevant than ever as a result of the considerable number of immigrant students enrolled in the Catalan educational system and the challenges this entails in terms of promoting social integration and language learning. Therefore, the objective of the study is to increase our understanding of language attitudes formation by analysing how origin (autochthonous or immigrant) influences (a) the attitudes toward Catalan and Spanish and (b) the effects of several demographic and socio-psychological variables on these attitudes. Additionally, it aims to identify the most important determinants of these language attitudes. For this purpose, 1156 secondary education students from ten schools across Catalonia answered a language attitudes questionnaire, a sociolinguistic survey, and two language competences tests. The results showed that, generally, self-identifications and language uses were the most influential factors. Furthermore, origin moderated the relationships between attitudes and their determinants, indicating that the models traditionally used to explain the attitudes held by autochthonous students need to be revised to take into account the particularities of the immigrant population.Language attitudes have become more relevant than ever as a result of the considerable number of immigrant students enrolled in the Catalan educational system and the challenges this entails in terms of promoting social integration and language learning. Therefore, the objective of the study is to increase our understanding of language attitudes formation by analysing how origin (autochthonous or immigrant) influences (a) the attitudes toward Catalan and Spanish and (b) the effects of several demographic and socio-psychological variables on these attitudes. Additionally, it aims to identify the most important determinants of these language attitudes. For this purpose, 1156 secondary education students from ten schools across Catalonia answered a language attitudes questionnaire, a sociolinguistic survey, and two language competences tests.The results showed that, generally, self-identifications and language uses were the most influential. Furthermore, origin moderated the relationships between attitudes and their determinants, indicating that the models traditionally used to explain the attitudes held by autochthonous students need to be revised to take into account the particularities of the immigrant population. Attitudes inform and shape our experiences and reactions, as they help making sense of the world and guide decision making by providing cognitive simplicity, i.e., dividing the universe into things one likes, dislikes, or has no opinion about (Fazio 2000; Fazio and Roskos-Ewoldsen 2005; Heining-Boynton and Haitema 2007). Accordingly, language attitudes are a powerful force in framing and solving language related issues, which makes them especially relevant in multilingual settings, where different languages coexist and peo...