This paper focuses on the use of Catalan, Spanish, and English in Catalonia, Spain, where Catalan and Spanish are official languages. The school curriculum includes at least three languages (Catalan, Spanish, and English) and Catalan has become the main language of instruction. The paper summarizes the use of the three languages in the curriculum and the teaching conditions and describes in more detail the teaching of English as an additional language within the bilingual educational system. It also reports the results of two studies on language achievement in the three languages and attitudes toward English. The paper also identifies the strong and weak points of the present linguistic situation in Catalonia as related to attitudes toward trilingualism and proficiency in Catalan, Spanish, and English. According to the research results one of the main challenges in the near future is to improve the level of proficiency in English.