BACKGROUND AND OBJECTIVES: In the context of accelerated global aging and increasing insufficiencies in long-term care delivery, older people are encouraged to provide informal support to each other within their communities. However, the mechanisms facilitating such informal support among older people remain unclear. This study aims to address this gap by investigating the perspectives and experiences of various stakeholders involved in initiatives aimed at stimulating informal support in the community. RESEARCH DESIGN AND METHODS: A qualitative multiple-case study was conducted in five Dutch initiatives stimulating informal support. Semi-structured interviews were conducted with a total of 23 different stakeholders and relevant documents were analyzed. An abductive thematic analysis approach was used for data analysis. RESULTS: Our analysis shows that community-based initiatives stimulate mutual support among older people by providing a coherent set of activities and facilities that indirectly, through community building, and directly influence individual behavior. On the community level, initiatives strengthen social cohesion, in terms of for example shared values and feelings of belonging. On the individual level initiatives create opportunities to provide support, help individuals to recognise and strengthen their abilities to give support and stimulate individual motivation. DISCUSSION AND IMPLICATIONS: Our findings underscore the need for policies that support informal care through complementary processes, which work in tandem with formal care systems. Policies and practices taking the identified mechanisms into account are likely to stimulate older people to provide informal support to each other in the community, thus enhancing aging in place.