Purpose: The purpose of this article is to develop and test a model to explain students' willingness to participate in sustainability programs. Specifically, the authors aimed to determine those factors, apart from students' environmental orientation (self-perception of "being green"), that influence students' willingness to participate in sustainability programs. Design/methodology/approach: A survey was conducted at one of the largest Australian universities, with 168 student respondents. A linear regression model with a bootstrapping method was applied to estimate direct and indirect effects. The model tested the indirect effects of three mediators: concern for environmental issues, educational activities, and promotion of university sustainable initiatives. Findings: The results from the empirical study show strong support for indirect effects. While students' environmental orientation is an antecedent of their willingness to participate in sustainability programs, the strongest mediator in this process is concern for environmental issues, followed by university educational activities and university promotion of sustainable initiatives. Originality/value: This is the first study set in an Australian University that analyses those factors affecting the students' degree of willingness to participate in university-initiated sustainability activities. The findings from this study are of interest to the higher education sector which plays an important role in both raising environmental awareness among students, and nurturing them as environmentally responsible members of the global community. The results of this study can be used to encourage student participation in on-campus sustainable activities which can be carried over when they graduate. (Contains 2 tables and 1 figure. Contains a citation for further reading.)