Upgrading biogas to biomethane is essential for improving its quality, allowing it to be injected into the natural gas grid or used as a vehicle fuel. Additionally, with the growing emphasis on environmental awareness, the responsible utilization of biogas and appropriate user applications with positive environmental impacts has become a key focus in technological development. This section reviews recent research on various upgrading methods, including three primary approaches: membrane separation techniques utilizing from organic, inorganic, and mixed matrix membranes; solid and liquid adsorbents; and biotechnological upgrading methods. The discussion will cover a range of technologies involved in these processes, emphasizing their efficiency, economic viability, and environmental implications. This comprehensive overview aims to inform future research and development in the field of biogas upgrading.