National non-governmental organisations (NNGOs) in Ghana are confronted with declining external donor funding, arising in part from the country’s graduation to a lower–middle-income status, but also more complex changes in donor funding modalities. This presents incentives the for mobilisation of alternative domestic resources to ensure organisational sustainability. Drawing on 62 qualitative interviews with NNGOs’ leaders, donor representatives and key informants, this article presents findings on how NNGOs in Ghana are responding to this challenge. Using Edwards’ idea of funding ecosystem, this article finds that NNGOs mobilised five main domestic resources: (a) volunteer support; (b) individual donations; (c) commercial activities; (d) corporate philanthropy and (e) government funding. The findings shed useful insights on the applicability of democratic, commercial and institutional elements of the funding ecosystem in contexts experiencing aid reduction and donor exit. This article concludes that while external donor funding is an immediate threat to civil society space in Ghana, social innovations in domestic resources in response to it offer limited potentials for NNGOs’ financial sustainability due to capacity challenges and the absence of an enabling environment that promote domestic philanthropy. Implications of the research findings for NNGOs’ sustainability and domestic philanthropy are discussed.