Universal design for learning as a framework for designing instruction that assumes the diversity of all students and provides flexible and intentional means for ensuring learning has been around for close to twenty years. Over the years, the framework and its understanding have considerably evolved. In this research project, we interviewed 19 experts in UDL. The group of participants consisted of experts conducting current research on UDL as well as those with historical background in UDL. The findings focus on experts’ perspectives on UDL’s definition, measurement, relationship to policy, and other issues.