This article provides a typology of reasons for conducting mixed-methods research in special education. The mixed-methods research process is described along with the role of the rationale and purpose of study. The reasons given in the literature for utilizing mixed-methods research are explicated, and the limitations of these reason frameworks are identified. We build on these frameworks by providing a comprehensive list of reasons for conducting mixed-methods research. The reasons provided in our model are operationalized in the context of special education and, thus, complement the goals of special education researchers. Finally, we present a four-dimensional Rationale and Purpose (RAP) model demonstrating how investigations can be designed according to the rationale for using mixed methods, purpose of mixing, stage of study where mixing occurs, and emphasis of approach derived from the research question(s). (Contains 9 figures, 4 tables and 5 footnotes.)