Social innovations (SIs) offer creative solutions to complex social problems and often require the exchange of necessary resources, knowledge, and expertise among various actors. These actors form an ecosystem that can support the development of successful SIs. In this special topic forum introduction, we first discuss the literature related to the support function of ecosystems. We use the theoretical lens of prosocial behavior to explain the various types of support in an ecosystem. We argue that there are three archetypes of support in ecosystems, namely, altruistic, communitarian, and commercial support. Subsequently, we present the three papers accepted for publication in the special topic forum. One paper refers to the three support archetypes, although indirectly, while the other two refer to one specific archetype of ecosystem support for SIs. This introductory paper concludes with discussion on the opportunities for future research. Without a clear understanding of the different archetypes of support, it would be difficult for both scholars and practitioners to design vibrant ecosystems in assistance to SI.