The overarching purpose of this article is to provide an introduction to the use of rigorous single-case research designs (SCRDs) in special education and related fields. Authors first discuss basic design types and research questions that can be answered with SCRDs, examine threats to internal validity and potential ways to control for and detect common threats, and provide guidelines for selection of specific designs. Following, contemporary standards regarding rigor, measurement, description, and outcomes are presented. Then, authors discuss data analytic techniques, differentiating rigor, positive outcomes, functional relations, and magnitude of effects.