Biodiversity is often believed to be economically valuable, but it is unclear where its value stems from. To date, a number of economic valuation studies targeted biodiversity in highly diverse ways, yet there exists no consistent framework for valuing it. In this paper, a conceptual framework for the economic valuation of biodiversity is presented. By drawing insights from both ecology and economics, the ways through which biodiversity influences human well-being are identified. It is argued that biodiversity’s economic value has four sources: biodiversity contributes to ecosystem functioning (insurance value), is the carrier of future options (option value), provides ‘efficient’ support for migrating species (spill-over value) and influences the aesthetic appreciation of ecosystems (aesthetic value). Being only a property of ecosystems, it does not have value per se, but only contributes to the overall value of an ecosystem. The paper also includes a discussion of the conceptual framework’s fit within the conventional TEV framework, from which the need is derived to expand TEV to better account for biodiversity; a possible extension is offered.