Engineers, facing increasingly complex problems, need to understand the technical and contextual aspects of their work to develop effective solutions. Assessments of comprehensive systems thinking skills are needed to support the development of these skills and to inform professional placement. Thus, our study investigated current systems thinking assessments in engineering by systematically reviewing existing assessments. We analyzed which systems thinking skills were emphasized, how they were evaluated, how data were collected and in what content areas assessments were based. The results revealed a range of assessments, in terms of type, format, and content area, but a lack of assessments that equally prioritized accounting for technical and contextual considerations. This overview of assessments can be used by employers and educators to select assessments appropriate for their contexts and goals. Overall, this study demonstrates a need for comprehensive systems thinking assessments that evaluate performance.