Social investment in East Africa is a nascent but fast-growing phenomenon with immense potential to realize the achievement of the sustainable development goals. It plays a very important role in the financing of a plethora of development sectors in East Africa, for instance, financial inclusion and poverty eradication, health and well-being, education, responsible energy production and consumption in the region. This article applies a mixed methods approach to carry out a non-exhaustive landscape analysis of the social investment market in East Africa with a keen focus on Kenya, Uganda and Tanzania. Based on relevant literature, available secondary data and a survey administered to social investors, this article applies the basic social investment market framework to highlight the dominant players in the demand and supply market spheres. The findings show that the supply of investment capital is misaligned with the demand from organizations and businesses and demand outweighs the supply. This article further analyses the challenges faced by the social investment players and also provides viable recommendations to drive the scale of social investment in East Africa.