System models are commonly used in tertiary education as a mechanism for describing the interacting components of educational phenomena, but have hitherto been uncritically accepted. This paper provides a critical review of existing systems models, including the 3P model defined Biggs, and outlines their conceptual challenges. A revised model developed for curriculum research is presented. The paper would be of interest to those undertaking education-focused research, scholarly teaching practitioners as well as those with an interest in the use of systems models as a framework for educational alignment.