Little consideration has been given to the process of technological change in political theory. Given that ideas about this process play an important role in many strands of normative political thought, and are especially crucial to climate change politics, this is a remarkable oversight. It risks political theory being irrelevant to climate change mitigation. The implications of this oversight for political theory are explored here through an analysis of the liberalism-ecologism debate. The article argues that attempts to green liberalism – to move it beyond environmentalism – cannot succeed while liberalism is silent about technological change. More broadly, given that most political theory traditions make claims about technological change, claims crucial to their worldviews and normative goals, it argues that much more theorisation of the concept is necessary. Especially now that they shape how the world understands climate change mitigation, contests over the meaning of technological change are intensely political contests. Political theory needs to get much more involved.