Chapter 6 explores the question: how does plate tectonics help drive long-term climate change? This exploration begins by examining the fundamentals of plate tectonics – the nature of tectonic plates, the three primary types of plate boundaries and their important processes, and the history of study that led to modern plate tectonic theory. Because plate tectonic processes act relatively slowly, the effects of those processes on climate are observed primarily over long timescales (millions of years or more). Plate tectonic processes can affect the distribution, storage, and movement of carbon between the Earth’s surface and subsurface through volcanism, mountain-building, and subduction, thereby affecting long-term climate. The tectonically controlled locations of continents on Earth, as well as the opening and closing of oceanic gateways, also have been important controls on Earth’s long-term history of Greenhouse and Icehouse climate states.