The notion of sustainable development has emerged as the dominant global discourse to adapt societies and economies to novel modes of production and consumption in areas such as transport, energy, housing, agriculture and food. This process can be described as a socio-technical transition, which means that along with the technological development it requires corresponding changes in markets, user practices, discourses in terms of policy and culture and governing institutions (Geels, Hekkert and Jacobsson, 2008). Entrepreneurs are considered essential agents of this transition. However, individual entrepreneurs do not have the ability to produce such change alone. Especially in emerging industries, entrepreneurs have to interact with skeptical external resource holders (suppliers, creditors, customers, etc.), while competing with incumbent firms that are committed to, invested in and advantaged by existing ways of doing things in a particular field (Garud et al. 2007). Therefore, entrepreneurs have to strive to gain legitimacy with different groups of stakeholders to get access to resources, markets, etc. as well as to be perceived serious and trustworthy (Aldrich and Fiol, 1994). This paper aims to study how entrepreneurs in the environmental technology sector use collaborative means to overcome resource, ability and legitimacy constraints in the process of commercialization of eco-innovations.