Many evolutionary processes are influenced by environmental variation over space and time, including genetic divergence among populations, speciation and evolutionary change in morphology, physiology and behaviour. Yet, evolutionary biologists have generally not taken advantage of the extensive environmental data available from geographic information systems (GIS). For example, studies of phylogeography, speciation and character evolution often ignore or use only crude proxies for environmental variation (e.g. latitude and distance between populations). Here, we describe how the integration of GIS-based environmental data, along with new spatial tools, can transform evolutionary studies and reveal new insights into the ecological causes of evolutionary patterns.