Sacred groves are sacred natural sites in patches of virgin forests that are protected by autochthonous communities as abodes of local guardian deities. Although found throughout the hills and plains of India, sacred groves are most commonly located in the biodiversity-rich ethnic areas of the Eastern Himalayas and the Western Ghats. Sacred groves share certain common features that include a small or large tree cover. These culturally protected natural habitats can effectively safeguard the local biodiversity. These informal institutions predate the existence and supplement the functions of the formal ones. The chapter outlines the role of sacred groves of India in in-situ conservation of ethnomedicinal plants. There are numerous reports on the wealth of ethnomedicinal plant species found in the sacred groves across India. These relic forests function as natural resource bases for the local communities by harboring key biological resources including ethnomedicinal plants. These medicinal plant resources are vital to the well-being of remote communities who still depend on traditional herbal remedies for their primary healthcare. Sacred groves have little or no human interference due to the customary restrictions on their access and biomass extraction activities. The smaller groves are virtually inaccessible, but the larger ones allow limited harvesting through sustainable resource management practices. This is commonly in the form of natural resource-related social taboos 230of the local communities which prevent overharvesting of plant resources including ethnomedicinal plants. The community-based traditional management practice in these sacred groves also checks degradation of natural habitats of medicinal plants and supports a rich plant spectrum of which they are an important part. These traditional repositories of local medicinal plants also function as the last refuge for ecologically important and fragile plant species with medicinal value. These ancient ethnoecological institutions involving the stewardship of the local communities provide a decentralized, inclusive, and participatory model for the in-situ conservation of the wealth of indigenous medicinal plant species of India.