Today humanity uses, on average, the equivalent of 1.6 earths toprovide the resources we use and to absorb our waste. A pathwayto sustainable resource use is the circular economy. This conceptaims at optimising the value of the resources used and to minimisethe amount of resources used. The author addresses the question ofwhat kind of law we need to realize a circular economy. He arguesthat many legal frameworks and rules on the national and theEuropean level will have to be reconsidered, amended and somecompletely newly framed to foster a truly circular economy.This is the inaugural lecture which Professor Chris Backes deliveredon 12 April 2017 on the occasion of accepting the Chair ofEnvironmental and Planning Law at Utrecht University School ofLaw, Utrecht Centre forWater, Oceans and Sustainability Law.