Hybrid organisations are ‘organizations that combine institutional logics in unprecedented ways’ (Battilana and Dorado, 2010, p. 1419; Scott, 2001); they thus bring together logics from different, and often conflicting, fields into a singular organisational form. Social enterprises, for example, are typical hybrids that combine economic, social and environmental goals (Battilana and Lee, 2014; Billis, 2010; Doherty et al., 2014) and have been found to operate successfully in diverse sectors such as microfinance (Battilana and Dorado, 2010), fair trade (Huybrechts, 2012) and work integration (Pache and Santos, 2013). Although exploiting business methods to address social or environmental problems might suggest an organisational model that combines the best of both worlds, categorical confusion has been found to limit an organisation’s access to resources and negatively impact upon long-term survival (Tracey et al., 2011). Hybridity in organisations is not a new phenomenon (Billis, 2010), but interest in innovative organisational models that facilitate the achievement of double, or triple, bottom lines has recently flourished in response to global sustainability challenges (Hoffman et al., 2012). Hybrid organisations, however, face legitimacy challenges in that they are: (1) difficult to categorise within established organisational taxonomies (Aldrich and Fiol, 1994; Suchman, 1995); and (2) held to account to multiple institutional demands by audiences that use different and possibly contradictory legitimation criteria (Kraatz and Block, 2008). In turn the credibility of their claims of commitment to different sets of standards may be deemed to be unconvincing. Securing the conferment of legitimacy from stakeholders is therefore an important challenge facing hybrid organisations. Previous research, however, has not investigated the activities required to build legitimacy when an organisational form bridges two or more institutional categories.