This chapter will discuss accessibility issues related to online education. It will provide rationale for designing online courses that cater to different levels of functional ability. It will also present an overview of the challenges faced by students with disabilities in accessing and interacting with online course materials and activities. In order to address the potential barriers to full participation, national and international guidelines will be examined, with particular emphasis on their implications for specific course components. In addition, mechanisms for validation of web accessibility will be suggested and resources will be listed for those interested in obtaining further information on the topic.