The number of postsecondary education (PSE) programs for individuals with intellectual and developmental disabilities (IDD) has been steadily growing over the last few decades. There has been little public information regarding these programs and schools. Consequently, students, families, and researchers alike lack details about the various postsecondary options available to students with IDD. In response, the researchers developed a taxonomy to delineate the characteristics of PSE programs for individuals with IDD, laying the foundation for further study and development. The taxonomy was developed in two phases. Using a case study approach, a diverse range of 21 programs in 2- and 4-year institutions of higher education were selected. Information was gathered from each program through interviews with disability service staff and program directors, and through a review of program documents. After creating an initial taxonomy from interview and document data, a validation phase was conducted using an online survey. The iterative process of analyzing the in-depth interview data, program materials, and survey responses, as well as constructing a logical, well-ordered taxonomy resulted in a structure that has 4 domains, 16 components, and over 100 elements. The PSE Taxonomy provides a mechanism for combining elements to provide a more comprehensive understanding of PSE programs, to clarify differences and similarities between programs, and to develop succinct, easily comparable program profiles.