To date, scholarly understanding of external dimensions of market driving for the purposes of 'societal change' is largely unexplored in both developed and emerging market contexts. This paper uses a multiple case study approach to understand how market driving social enterprises (across the hybrid spectrum) create societal change in emerging markets. By drawing on Scott's (1995) three-part conceptualization of institutional legitimacy, this study explores how regulative, normative and cognitive legitimacies are invoked by market driving social enterprises at the Bottom of the Pyramid (BoP). Key contributions of the study show that all three dimensions of legitimacy are relevant but they need to be invoked in a specific order based on necessary and optional conditions. An implication of the study is that market driving through societal change can lead to the construction of new and more inclusive healthcare markets.@en