Evaluating accessibility is an important equity step in assessing the effectiveness and usefulness of online learning materials for students with disabilities such as visual or hearing impairments. Previous studies in this area have indicated that, over time, university websites have become gradually more inaccessible. This paper relates findings of a quantitative, comparative study of university website accessibility for students with disabilities. Sampling comprised a random selection of 20 universities from each of the Academic Ranking of World Universities top 100, Oceania region top 50, and Arab region top 50 ranked universities. AChecker evaluations of three types of website from each university--the home page, the admission page, and a course description page, revealed a total of 30,944 accessibility related home-page errors among the 180 evaluated webpages. Comparison with earlier studies reveals no significant improvement in the accessibility of university websites between 2005 and 2015. There were also no differences in accessibility levels amongst the selected top-ranking universities in the world. Therefore, there is a growing need for universities to improve accessibility of online learning materials for students with disabilities.