Calls for ‘climate justice’ are everywhere, from the hallways of international negotiations to the streets. Governments justify their policies in the name of climate justice, while activists sometimes denounce those same policies on climate justice grounds. But what does it mean to respond to climate change justly, and is this the same thing as pursuing climate justice? The academic literature on climate ethics has tended to focus on what it means to respond to climate change justly, while the climate movement has tended to focus on how to achieve ‘climate justice’. This chapter is arranged in two sections. The first introduces climate justice as an ethical question, and the second introduces climate justice as a political question. But neither of these questions can be adequately answered without reference to the other, so understanding climate justice requires deliberate and careful attention to the relationship between them.