While learning at scale has the potential to widen access to education, the accessibility of courses offered on Massive Open Online Course (MOOC) platforms has not been researched in depth. This paper begins to fill that gap. Data was gathered using the participatory ‘Evidence Café’ method. Thematic analysis identified characteristics of accessible courses on these platforms. These characteristics include elements of both technology and pedagogy. Capturing and analysing expert insights enables this paper to provide guidance on how online courses can be made more accessible. The findings suggest that course production teams need to work collaboratively with providers to address issues of accessibility and involve learners in design, testing and evaluation. Well-designed tutor-supported activities that follow web accessibility and usability guidelines are needed, as well as educator training on accessibility.