Globally, bio-based business is often perceived as sustainable, because its renewable production can potentially lower carbon and greenhouse emissions by substituting fossil-fuel-based production, reduce environmental sourcing problems, and create turnover and jobs. However, bio-based business can also bring sustainability challenges. Urged to exploit innovative solutions and further enhance their sustainability performance, organizations engaged in bio-based activities extensively search for collaboration possibilities with new partners. Inter-organizational collaboration is considered as mechanism to enhance sustainability. This thesis explores the ways inter-organizational collaboration in bio-based business in general and in agro-industrial parks in particular can enhance sustainability.