Fab Labs as manufacturing laboratories that stimulate innovation and collaboration are nowadays proliferating within universities. Given the new social challenges, framed within the Sustainable Development Goals (SDG), we formulate the following research question: Are Fab Labs an effective tool for the promotion of social innovation from universities? To answer this question, a mixed analysis has been carried out focusing on the case of ProteinLab UTEM. The approach aims to generate a model for the promotion of social innovation from universities through Fab Labs, linking the quadruple helix actors. The objective of this model is to show how Fab Labs can become an effective instrument to promote social innovation from universities. The contribution of this article lies in linking Fab Labs with social innovation through the university's third mission. Our approach considers Fab Labs as an instrument for the development of social innovations within the university, which contribute, through the third mission, to the social and sustainable development of its environment. As a result of this research, a model is presented for the development of social innovation from universities through Fab Labs. Our research concludes that Fab Labs are an effective instrument for the promotion of social innovation from universities.