Threshold concepts are those transformative concepts in a discipline that are often difficult to understand when first encountered, but when mastered they transform students, both epistemologically and ontologically in relation to the discipline. Using the characteristics of threshold concepts, existing curricula and summative content analysis of the text in published seminal geographical information systems (GIS) research papers, this study identifies three key GIS concepts as threshold concepts which are map-scale, data model and interoperability. This study further links these concepts with other key GIS concepts with the aim of providing a means for laying conceptual foundation among novice GIS learners.