This article builds on earlier conceptual models of identity development to propose a model of heterosexual identity development. A review of the existing literature on majority and minority group identity development, heterosexuality, and other relevant foundational literature is provided as a rationale for the proposed model. Based on an analysis of the strengths and limitations of the existing literature, the authors propose a preliminary model of heterosexual identity development. The article concludes with implications for research, practice, training, and measurement in counseling psychology.