Technology social ventures (TSVs), a form of hybrid ventures, are among the most important and impactful forms of entrepreneurship. Like new social and commercial ventures, scaling is important for new TSVs to become established firms. Yet, what constitutes scaling is significantly different for TSVs as compared to other forms of ventures, namely, not-for-profit social organizations and profit-driven commercial ventures. However, scholarship is fragmented over defining scaling in TSVs. Therefore, the first objective is to contribute to the definition of scaling TSVs. To meet the first objective, we conduct an adapted Delphi study, where we formulate a literature-driven and expert-ratified definition of scaling TSVs. Our second objective is to identify founders' leadership styles to aid scaling in TSVs. In the second study, based on our scaling definition, we identify three scaling TSVs, and then, using a multiple case study approach, we explore their founders’ leadership styles that aid scaling. It emerges that the founders do not use a single leadership style but use a combination of transformational and transactional leadership styles. Interestingly, it emerged that founders used humble leadership styles. Using these leadership styles, founders encouraged high performance and created an environment that aided scaling.