This chapter studies green criminology, a strand of criminology that looks at crimes against the environment, animals, and non-human nature that are largely ignored by mainstream criminology. Green criminology takes a critical approach, looking beyond narrow, human-centred definitions of crime to consider a wider conception which some see as a form of social harm. Green criminologists examine a wide range of environmental issues, from wildlife crime, wildlife trafficking, animal rights, and species justice to corporate environmental crime and illegal pollution, ecological justice and ecocide, food crime, and the links between organised crime and the waste industry. The chapter looks at how environmental issues are sometimes neglected by markets, the criminological concepts and theoretical approaches associated with green criminology, and the debate about whether we should focus on green crimes or harms. It also considers how environmental harms are regulated and the different ways of responding to and policing green crimes.