Research shows that the information systems domain is underrepresented in project complexity as it has only eight percent representation within the project complexity landscape. Emphasis is placed mostly on generic project management and engineering project management. This begs the question of how well IS project complexity is understood in literature? The goal of this research is to perform the groundwork for developing new theoretical foundations for information systems (IS) project complexity by enriching previous work. Complexity theory was applied to develop a comprehensive theoretical model for IS project complexity. The IS project complexity (ISPC) model was developed and revealed that 10 elements underpin the complexity of IS projects. The model expands on previous research by including a larger array of IS project complexity elements and their inherent features. The ISPC also goes beyond the project itself, as it considers elements such as the organization’s strategy, resource management, and structure.