Despite the critical role that faculty play in the success of students with disabilities in higher education, professional development for promoting the understanding of these students' needs and the employment of inclusive instructional strategies to enhance their success has been limited. To better assess the potential of the online environment as a context for professional development, this mixed methods study investigated the impact of an online disability awareness program designed to introduce college faculty to Universal Design for Instruction (UDI) principles. The study followed a sequential design consisting of two phases. In the first phase, 43 faculty members completed pre- and post-program surveys measuring attitudes toward and knowledge of students with disabilities. In the second phase, we conducted a thematic analysis of interviews with 10 faculty participants who completed the program one semester earlier. The quantitative and qualitative phases resulted in three convergent findings: participating in online professional development led to increased faculty knowledge, improved faculty attitudes, and the emergence of faculty confidence in applying UDI principles for better accessibility of course materials and content presentation. The results indicate that professional development programs in an online context are a promising means for providing faculty the support they need to enhance their teaching practices and promote inclusive learning environments.