The study of economics involves core issues of sustainable development very relevant to society, such as growth, consumption or wellbeing. Accordingly, its epistemology and teaching contents influence other disciplines, the conception of society and the political agenda. From this perspective, it is strategic that the teaching of economics promotes sustainable development. The aim of this article is to examine what the subjects of economics and business economics teach about sustainability at the upper secondary education level in Spain, and if they contribute to the acquisition of the key competencies of the education for sustainable development. A content analysis is carried out of both the curriculum and the textbooks to that end. Our results emphasise that the ideas, concepts and values transmitted by the Spanish upper secondary economics textbooks do not adequately promote knowledge about sustainability or the learning of the key competencies.