AbstractThe intent of this paper is to provide a brief description and critique on each of the 4 pillars of SysML. The description will cover in detail the type of modeling elements used in each pillar, the relationships between these elements, and the views used to represent the model data. The analysis and critique offered will follow the description for each pillar and is primarily from a functional perspective, covering the strengths, weaknesses and identified gaps in the language. In some cases, a recommendation for potential improvement will be provided. Additional modeling gaps that apply across all pillars will also be identified and discussed. Addressing current gaps in SysML would improve our capabilities to accurately represent a system in a modeling format and help better communicate the model to customers in support of a life cycle systems engineering process.