Purpose This paper aims to compare the environmental sustainability practices at the campus operations between two Portuguese higher education institutions (HEIs) at different stages of the implementation of an Eco-School Programme. It also seeks to analyse the involvement of the students in the process of implementing these practices in their institutions. Design/methodology/approach A questionnaire survey was carried out in two HEIs (a green and a non-green institution). Data were collected from a total of 832 students. Techniques of descriptive statistics and inferential statistical techniques such as the Mann-Whitney test, χ2 and Spearman correlation test, were applied. Findings The results obtained show that, from the students’ perspective, and in both institutions, there is still much to be done on the path towards sustainability, particularly in transport and landscaping. Significant differences were found only between some environmental sustainability practices at the campus level. However, students from the green institution are more participative in sustainability activities. Practical implications This study provides a picture of two HEIs’ sustainability behaviour from the students’ standpoint, which can be important for decision-makers in HEIs, in as much that students are one of the HEIs’ major stakeholder groups; furthermore, it enables them to better guide their efforts towards sustainability. Originality/value This paper focusses on the students’ perspective and their role in the sustainability initiatives undertaken by HEIs. It can be useful for future research that attempts to analyse the importance of HEIs’ stakeholder participation in sustainability.