Adult education instructors are as diverse as the students they teach. Their professional backgrounds, training, licenses, and modalities of teaching (online, in person, open vs. closed enrollment, etc.) vary widely, which can make the planning of meaningful, effective professional development challenging. Universal Design for Learning (UDL) is a research-based educational framework developed almost 30 years ago by CAST, a non-profit education research and design organization. Using the UDL framework, CAST has developed self-paced professional learning modules that can be accessed freely through the Literacy Information and Communication System website (https://lincs.ed.gov/). The goal of this article is to argue that two key UDL-based design concepts - accessibility and relevance - can be used to increase the effectiveness of professional development for adult educators.