Class is crucial for understanding why sustainability has become so much more popular at the urban than at other scales. The urban scale is where the capitalist class can most easily colour their investments ‘green’ without confronting the overall power of fossil capital. Urban sustainability has therefore become the limited answer to a question that should really be posed at other geographical scales. In this article I analyse the intersections between class and geographical scale to examine and criticize the class character of the sustainable city. I use a stratification approach to identify the irony of people with high carbon footprints tending to live in the ‘greenest’ cities or city districts. This is class in the sustainable city. A Marxist understanding—not least one emphasizing the capitalist class as a class—can help us grasp the class character of urban sustainability. This latter approach helps us identify how class produces urban sustainability.