The authors conducted professional development (PD) for university personnel, focused on Universal Design for Instruction (UDI), over three days during a summer institute. The UDI-focused PD provided 20 hours of training across six content areas: (a) UDI, (b) accessible distance education and assistive technology, (c) student and faculty rights and responsibilities, (d) disability culture, (e) hidden disabilities, and (f) multiculturalism and disability. During the semester following the PD, a qualitative follow-up study was conducted to investigate faculty's implementation of UDI principles and strategies. Four individual faculty cases were analyzed to investigate the ways in which faculty applied UDI principles and strategies. Then, the cases were compared to detect patterns, and identify themes that explain variation in faculty's UDI implementation (Patton, 2015; Stake, 2000, 2006). Three interrelated themes emerged as potential factors influencing faculty's level of UDI implementation: the extent to which faculty (a) conceptualize UDI as an ongoing endeavor (versus a finite, achievable state); (b) engage in self-reflection; and (c) internalize a social model of disability. Implications for practice are discussed.