The impact of the generational cohort on language attitudes has almost never been explored. However, in particular in the bilingual territories in Spain, the literature emphasizes the importance of being Spanish-speakers or non-Spanish-speakers in the construction of these attitudes. Centering on the case of Catalonia (Spain), this article examines the influence of the family language and the generational cohort on the language attitudes towards Catalan and Spanish that is built by immigrant children (aged 14–16). The nature of the assay performed as a result of an attitude questionnaire answered by 527 young people permits differentiation of the effect of both variables individually when included in the same explanatory model. Results point out that being Spanish-speaking or non-Spanish-speaking is weighty in the construction of attitudes towards Spanish and towards Catalan. Moreover, the generational cohort is only weighty for attitudes towards Catalan and when a migratory transit has been experienced or not. Since both variables are included in the same model, it is proposed that the effect of the generational cohort is moderated by being Spanish-speaking or not. The novel perspectives opened up by these results are debated as regards the promotion of intercultural communication and a common project of coexistence.