In this research, we examine the scaling of a social enterprise through legitimacy. Using a qualitative approach grounded in a single case study, that of The Kalgidhar Trust Society from India (TKTS), the study examines the external strategies and internal process to examine the scaling of TKTS with a special focus on its chain of schools, the Akal Academies. We develop a model where internal and external legitimacies lead to scaling up and scaling wide and build socio-political legitimacy, which in turn spreads the values of the organisation and creates a deeper impact in society. This paper introduces the legitimacy lens to scaling, which has not yet been sufficiently explored in literature.