A core goal for sustainable development is the protection of the natural environment, which provides a foundation for all life on Earth. But, despite widespread consensus that environmental conservation is important, many ecosystems continue to be degraded, and biodiversity is on the decline globally. In response to this paradox, many scientists, activists, and policy-makers call for the natural environment to be valued more. Yet, how to define, measure, and govern environmental values is a matter of great controversy in itself. This chapter seeks to provide an overview of these politics of environmental valuation. It begins by outlining how different disciplines (economics, philosophy, psychology) have traditionally considered environmental values. It introduces core debates around various types of environmental values, explaining a range of specialist terms and varying ethical perspectives on the value of the natural environment. It then discusses multiple methods for environmental valuation, in particular, monetary valuation of the environment, which has become ever-more popular since the late 1990s. While some believe that such monetary valuation can be a game-changer for environmental conservation, others have warned about the risk of commodification that it may entail. Ecological economists, in particular, have expressed concerns that monetary valuation can be a stepping stone towards formerly public or collectively managed environmental goods being appropriated by private entities and exchanged for money in market transactions. This chapter also considers alternatives to monetary valuation, including the possibility of using deliberation to elicit environmental values for policy-making, as well as the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services’ (IPBES) conceptual framework; in particular, the concept of ‘nature’s contributions to people’ (NCP).