Student entrepreneurship is becoming more relevant for universities throughout the world. Therefore, it is important to analyze the strategies and mechanisms adopted by universities to support student entrepreneurship. In this article, we analyze the mechanisms used by universities to promote student entrepreneurship through University Business Idea Incubators as part of their Third Mission. University Business Idea Incubators can act as preincubators or preaccelerators that are designed to help a growing number of university students from different backgrounds interact and develop their entrepreneurial ideas in a safe and creative environment. In such a context, we performed a cross-case study methodology on a national program that is aimed at creating Italian University Business Idea Incubators. As a result, we have identified the five key features and 12 strategies adopted by University Business Idea Incubators to cultivate student entrepreneurship. The article also presents some examples of successful business ideas developed by students as a result of their participation in University Business Idea Incubators. The obtained results also demonstrate how University Business Idea Incubators foster intellectual capital to sustain the development of an entrepreneurial mindset and competences, with the objective of favoring both the creation of concrete new ideas and of offering new challenge-based learning approaches to university students. We also offer some ideas that could be incorporated in educational policies to support university student entrepreneurship.