The growth of wildlife and environmental crime has catalysed efforts to strengthen state policing to better exert control over activities, flows, and people that threaten states’ desired socio-ecological orders. The expanded role of policing in and over human-environment relations provokes conceptual and empirical imperatives to better centre policing in political ecology and political geography scholarship on state-environment relations. This article begins with the question of how political ecology might better account for and conceptualise policing power, and how doing so can help understand how, where, and through what practices and institutions states exercise power over socio-ecological relations. To capture the role of policing in exerting power and control over socio-ecological orders, this article brings together insights on critical theories of police power, conservation power and state power to develop the concept of police power in green. I argue that police power in green grounds the mechanisms through which state power is exerted over socio-ecological relations in ways that reflect a broader strengthening of state power. I use multi-scalar and ethnographic research to examine three processes that extend and expand police power in green, and related state power. These are: 1) expanding conservation law and criminality beyond conservation spaces to national territory; 2) creating new environmental police bodies; 3) strengthening and expanding traditional policing, enforcement and criminal justice institutions. I end by outlining how police power in green can connect and further critical scholarship on political ecologies of the state and broader debates on policing, the green state and state power.