Biodiversity loss and climate change are urgent, interlinked crises, driven by human activity. The solutions to these crises therefore lie in changing people's behaviours, at both individual and societal scales. In this chapter, we introduce the Behaviour Change Wheel (BCW), a comprehensive framework for systematically designing, evaluating, and characterising behaviour change interventions. Applying the BCW to create behaviour change interventions for biodiversity conservation is discussed. A case study of national pollinator initiatives in the European Union is provided, to demonstrate how the BCW can be used to evaluate and characterise content within existing interventions and policies. Practical implications for applying behaviour change theory to the biodiversity crisis are outlined. To bend the curve of biodiversity loss and tackle other environmental challenges, those working in nature conservation, climate change, and other areas of pro-environmental behaviour are encouraged to apply the BCW to develop effective, theory-based interventions to change human behaviour.