Existing global protected area networks have two shortcomings: they do not cover certain habitats, and local people often resent their formal management. Here, we show that communities around the world traditionally protect natural sites that are dedicated to ancestral spirits or deities. Such sites cover a wide variety of habitats and are often located in biodiversity rich regions. Case studies on sacred groves show that these small forest patches play an important role in biodiversity conservation. Furthermore, natural sacred sites are maintained through traditional methods of community based conservation that do not require governmental involvement. Incorporating these sites into conservation networks could enhance the effectiveness of protected areas by covering a wider variety of habitats and by harnessing the support of local people. In this article, we discuss current threats to sacred groves that need to be addressed through management approaches. More research on the ecology and underlying socioeconomic mechanisms of natural sacred sites is required to fully reveal their potential for biodiversity conservation