Sacred groves or sacred natural sites (SNS) are defined areas of land and bodies of water with considerable socio-cultural and ecological value. This study attempts to analyse SNS using the framework of commons or common-pool resources and understand the implications regarding the access to and ecological sustainability of these sacred spaces. A set of ten groves from an inventory of sacred groves reported by the Institute of Foresters Kerala were chosen using purposive sampling to cover various types of custodianship and communities in the district of Thrissur. This district houses the most famous sacred grove in Kerala and is known for consecrating sacred groves and expunging spirits. A field survey employing an observation schedule and semi-structured interviews were undertaken focusing on the biophysical, socio-cultural, and institutional aspects of the SNS. Understanding the relationship between grove ecosystems and stakeholder communities was the objective of the study. The management of SNS in the study sites does not show much evidence of collective action. There is a tendency of SNS to become 'club goods' over a period of time. Regardless of types of custodianship, SNS exhibit properties of common-pool resources from an ecological point of view. Even when customarily managed along caste lines, access was not physically restricted. Recent constructions of concrete boundaries around SNS, conversion of groves to temples, and increasing intensity and frequency of rituals have changed the socio-cultural and ecological character of these spaces. The study shows that the perspective of the commons is inadequate to capture the underlying power dynamics of institutions of SNS. Understanding the transformation of SNS from being 'open' and inclusive to closed and elitist temple spaces need a different language of political ecology.