Geographic Information System (GIS) skills are increasingly marketable across a wide range of industries, subject areas and specialized fields. As a result, GIS courses draw students from a plethora of disciplines beyond geography, including business, social sciences, agriculture, geology, natural resources and computer science. At advanced teaching levels, this disciplinary diversity generates questions about how complex GIS skills are being taught to students who do not necessarily have a background in geography or the spatial sciences. This study compares undergraduate and graduate course curricula to determine what topics, techniques and theory are being addressed and prioritized in GIS courses across pedagogical levels. We surveyed 1,698 courses being taught at 126 research universities in the United States. Our findings point towards a shift in pedagogy that favours technique- or application-centred lessons at advanced levels that require less background knowledge in geography than more theory-centred teaching methods. Our findings also suggest that a large number of graduate courses, even introductory courses ones, fail to address many fundamental GIS concepts and theories. Together, the results suggest a need for standards to ensure that students enrolled in GIS classes are properly trained to enter the workforce with appropriate skills.