This commentary on the special issue, entitled "Models and Tools for Systems Learning and Instruction," highlights the accomplishments of the papers in this collection. It also points to some avenues for further strengthening research on promoting systems understanding. Collectively, the papers make advances in our understanding of how to design learning environments to foster systems understanding, how to develop teacher adeptness at orchestrating learning in these environments, and what processes mediate learning within the environments. The papers represent a diversity of methods for measuring learners' systems understanding, with different kinds of tasks and largely different coding categories for classifying responses; research could be advanced through systematic investigation of these different types of assessment and how they affect findings. Further progress could also be achieved through more detailed descriptions of instructional interventions and through incorporating more design-based research techniques to identify which features of learning environments are responsible for successes and failures in students' learning.