Purpose: This tutorial aims to introduce school-based speech-language pathologists (SLPs) to developmental systems theory as a framework for considering interactions across functional domains, such as language, vision, and motor, for students with complex needs. Method: This tutorial summarizes the current literature on developmental systems theory in its application to working with students who have needs in multiple domains of functioning in addition to communication. A hypothetical case of a student, James, with cerebral palsy, cortical visual impairment, and complex communication needs, is presented to illustrate the primary tenets of the theory. Results: Specific reason-based recommendations are presented that SLPs can put to practice with their own caseload in direct response to the three tenets of developmental systems theory. Conclusions: A developmental systems approach will be useful in expanding SLP knowledge of where to begin and how to best serve children with language, motor, vision, and other concomitant needs. The tenets, including sampling, context dependency, and interdependency, and the application of developmental systems theory can be instrumental in providing a way forward for SLPs struggling with the assessment and intervention of students with complex needs.