The Lower Mekong region is rich in biodiversity and forests that are vital for carbon storage. But illegal logging and illegal trade worth billions of dollars each year are causing extensive deforestation and harm to its people, the environment and the economy. Programmatic interventions to counteract forest crime seek to reduce demand for illegal forest products and create sustainable supply chains. In this context, effective communications and behavioural strategies are critical. The KAP score model, used in this handbook, measures knowledge, attitude, and practice related to forest crime and provides a step-by-step guide for designing communications interventions and behavioural change strategies to address illegal logging, illegal trade and other serious threats to the region's lush forests. An online version of this handbook is accessible at: www.un-redd.org/kaphandbook