International Journal of Innovation Management, Ahead of Print. Being embedded in an open innovation (OI) ecosystem can be the road to success for startups. In order to survive and become competitive, they must collaborate with external partners. Not only could large corporations be suitable partners, but innovation with small and medium enterprises (SMEs) can be constructive and fruitful as well. Furthermore, accelerators, incubators and other institutions can offer value to startups. Despite this fact, little attention has been paid to startups and SMEs embedded in OI ecosystems, especially from their point of view. The aim of this paper is to fulfil this research gap and deliver empirical data about the benefits and challenges of an OI ecosystem orchestrated by a startup and to investigate the potential role of an SME in these ecosystems. To answer the research questions, a case study approach was used.