Taking a socially proactive stance that aligns with their economic imperatives has led multinational corporations (MNCs) to focus on social innovation that tackles environmental challenges (or eco-innovation hereafter). Their knowledge of eco-innovation is important to emerging markets that are facing severe environmental challenges and to emerging market firms (EMFs) whose eco-innovation activities face resource and knowledge constraints. MNCs, through their foreign direct investment (FDI) activities in host emerging markets, can divulge economic, knowledge and environmental values of eco-innovation, helping EMFs to improve their eco-innovation through knowledge spillover channels. Taking the value-based approach, we draw on the eco-innovation research and the MNC/FDI spillovers literature to develop hypotheses on the relationship between regional knowledge spillovers of MNCs and the eco-innovation of EMFs in a multi-dimensional task environment characterized by munificence, complexity and dynamism. Our empirical examination is based on a sample of Chinese manufacturing firms from 2003 to 2013. We find support for hypotheses that regional knowledge spillovers of MNCs enhance the positive effects of munificence and mitigate the negative effects of complexity and dynamism on the eco-innovation of EMFs.