Responding to a number of longstanding challenges such as poverty, wide-ranging inequalities, environmental problems, and migration, requires new and creative responses that are often not provided by traditional governments. Social innovations can offer socio-ecological and economic solutions by introducing new practices that reduce social inequalities, disproportionate resource use and foster sustainable development. Understanding the role of social innovations is especially complicated in unstable institutional environments, e.g. in developing countries and countries in transition. This paper analyses nine social innovations in rural areas in Serbia, based on in-depth interviews and document analysis. This analysis reveals factors that facilitate or constrain social innovations whilst simultaneously identifying related formal and informal institutional voids, for example, poor law enforcement, a lack of adequate infrastructure, lack of trust, as well as norms and values that bolster patriarchal systems. The results that emerged from this research show that social innovations are operating in spite of these challenges and are facilitating improvements in a number of the aforementioned challenging areas. Some innovators engage in social entrepreneurship activities because of subsistence-oriented goals, while others follow idealistic or life-style oriented goals, thus creating new social values. Moving beyond these observations, this paper also identifies means to overcome institutional voids, such as creation of context-specific organisational structures, improved legal frameworks, and innovative financial mechanisms.