During the development of technological innovation projects, the team has difficulty to identify and managing uncertainties, which represents a challenge to bring the technologies closer to the market. Although there are studies on the management of uncertainties in innovation projects in different contexts of organizations, no studies were found relating to the adoption of Lean Startup (LS) practices and the management of uncertainties during the development of technological project processes in academic environments. Thus, this research aims to identify the uncertainties that can be mitigated during the development of these technological projects using LS practices. A multiple case study was conducted within a Brazilian federal university to fill this gap, analyzing nine technological innovation projects. The research consisted of identifying the uncertainties experienced by the project innovation development team before and after the application of LS practices. In the end, the uncertainties were analyzed in the context of each technological project, considering the mitigation achieved after applying the LS practices, and comparing them with their initial state. As a result, it was observed that the initial uncertainty categories most experienced by the project teams were related to products and resources, especially those related to knowledge and team profile. When evaluating the uncertainties after applying the LS practices, it was possible to observe that the most mitigated uncertainties were related to resources followed by the business model, the latter being the third most experienced in the initial scenario of the project development process. On the other hand, the uncertainties related to products were the ones that presented the least mitigation. Regarding resource uncertainties, the LS practices contributed to the mitigation, specifically those related to process quality, obtaining resources and knowledge, and team profile. As for the uncertainties observed in the business model, better results were observed specifically in those focused on marketing strategy, pilot production, and definition of the revenue model. It is concluded that the LS practices made more significant contributions to the business-related uncertainties than to product-related ones since product-related uncertainties were the ones that obtained the lowest mitigation results.