Purpose: This paper aims to analyze the characteristics and performance of university-industry (U-I) collaboration for knowledge transfer in relation to environmental sustainability, considering for both parties of the collaborations. Design/methodology/approach: The study is explorative in nature, based on an original data set of more than 350 U-I research and consultancy contracts signed by more than 70 professors specializing in environmental sustainability-related academic disciplines at the University of Padova (Italy) for the period 2008-2012. A mixed-method approach is adopted. Social network analysis and regressions are used to explore the impact of U-I on performance considering for characteristics of the firms, the professors and the collaboration. Interviews with key informants at University of Padova is used to complement and validate the emerging evidence. Findings: Results suggest that U-I positively impacts the performance of firms, but not of professors. Indeed, the hypothesis that professors' performance (measures in terms of academic publications) is positively associated with academic engagement is not supported. On the contrary, firms' financial performance is positively associated with U-I collaboration focused on knowledge transfer for environmental innovation; the higher the contracts activated the better the economic performance. Originality/value: While most previous research has focused either on the university or the firm side of U-I, this study looks at both sides and focuses specifically on engagement in green contracts. The analysis of the geographical scope of U-I collaborations contributes to the growing body of literature by outlining geography's role in U-I collaborations related to sustainability.