Universities around the world are showing an increasing tendency to respond positively to calls for sustainability on their campuses. As generators of knowledge through research, teaching and outreach, universities have a responsibility to create and maintain a strong environmental education base for all their students and users. In this context, this paper investigates the curricula of subjects that cut across more than one degree programme in a Higher Education Institution (HEI) in the Buenos Aires Metropolitan Area. The main objective is to identify subjects common to more than one degree or undergraduate course and to analyse how they are aligned with the key competences for sustainability. To this end, a survey was sent to the teachers responsible for teaching these subjects, which included criteria on subjects taught, time/unit coverage, specific competences, techniques and forms of assessment. The information gathered was used to compile the Higher Education Sustainability Indicator (HESI), assessing the competences in the dimensions of knowing, doing and being of the student and future graduate. Among the most relevant results, it is worth highlighting that the competences promoted by teachers focus more on reflecting (knowing and doing) than on acting (doing and being). Furthermore, it was identified that some graduates do not have competences for sustainability in their curricula due to the lack of compulsory or optional subjects with environmental themes. This forces students to seek extracurricular environmental training, which is limited at HEIs.