This article examines the language ideologies associated with the sense of self-efficacy of bilingual preservice teachers about their Spanish-language skills. Current teacher shortages in the field of bilingual education and increased professional demands placed over pre- and in-service bilingual teachers compel teacher education programs to adapt their designs to the needs of future teachers. These needs are determined, to a great extent, by the perceptions that bilinguals have over their own ability to use Spanish as a medium of instruction and to teach Spanish as a subject. Using grounded theory, the study sought to analyze how language ideologies impact the self-efficacy of bilingual preservice teachers. Results show that ideologies connected to the hegemonic position of English in society had a strong effect on the sense of self-efficacy of the preservice teachers about the Spanish language. Consequently, teacher education programs preparing bilingual educators need to oppose and counteract ideologies affirming the hegemony of the English language, proposing instead perspectives favorable to linguistic pluralism.