Green waste is biodegradable waste that can be comprised of garden or park waste, such as grass or flower cuttings and hedge trimmings. Green waste is often collected in municipal curbside collection schemes.

The green waste fraction of the over all waste stream is important as a biodegradable waste. If the waste is not either composted or anaerobically digested and it is disposed of in landfill it is an environmental liability. Biodegradable waste in landfill breaks down to biogas containing methane, which if not captured is a potent greenhouse gas and contributes to global warming.