In Spain, the learning of foreign languages has become one of the most interesting educational challenges in recent decades. Regulatory changes have been proposed to align with the Council of Europe’s language policy, which aims to promote plurilingualism and pluriculturalism among European Union citizens. Although the development of plurilingual competence in students has become a key goal, there is little evidence regarding the beliefs of current teachers, especially in monolingual contexts, where multilingualism is mainly developed through instruction. This study involved 307 teachers who taught languages or subjects in a foreign language. The results reveal beliefs about the promotion of plurilingualism, the objectives of language learning, the importance of plurilingual competence, and its characterization that at times do not align with the European language policy and its approach to plurilingualism, though there is agreement on other issues. Among the variables analyzed, two variables—academic training and the number of languages known—were found to significantly influence the beliefs revealed.