Background: Environmental problems are a worrying phenomenon, and there is a call for action. One way to face these problems lies in sustainable entrepreneurship. There is an increase in sustainability-oriented incubators supporting these sustainable entrepreneurs on their entrepreneurial journey, using various support systems. However, there is little research available about the support systems sustainability-oriented incubators offer, the importance of these support systems, and the influence of entrepreneurial stages. Purpose: With our study, we provide sustainability-oriented incubator managers with insights into the importance of different support systems, the frequency in which they are offered and the role of different entrepreneurial stages. This allows sustainability-oriented incubators to support their tenants better and, therefore, positively influence sustainable entrepreneurship.  Method: A single case study method has been applied by using a mixed-method approach of qualitative semi-structured interviews and a quantitative questionnaire which was filled in prior to the interviews by the participants. In total, nine participants were interviewed, consisting of seven incubator tenants and two incubator managers. Conclusion: This research has found a high level of importance and frequency of business model support and market research support, irrespective of the different entrepreneurial stages. This implies a constant reiteration process from sustainable entrepreneurs, demanding a strong-intervention role from the sustainability-oriented incubator. Furthermore, this research has found the shortcomings in using the effectuation model for analysing entrepreneurial stages and suggests a different application.