This article describes ethnographic decision tree modeling (EDTM; C. H. Gladwin, 1989) as a mixed method design appropriate for counseling psychology research. EDTM is introduced and located within a postpositivist research paradigm. Decision theory that informs EDTM is reviewed, and the 2 phases of EDTM are highlighted. The 1st phase, model building, is an inductive process consisting of a series of ethnographic interviews designed to describe and diagram the choices of decision makers. The 2nd phase, model validation, utilizes linear hypothesis testing borrowed from a quantitative research paradigm. During model validation, the group decision model is tested using a separate group of participants from the same population. Strengths and limitations of EDTM, and its potential applications in counseling psychology research, are emphasized.