This goal of this study was to examine the differences between lecturers and students' perceptions of the accessibility of instructional materials. The perceptions of 12 mature computing distance education students and 12 computing lecturers were examined using the knowledge elicitation techniques of card sorting and laddering. The study showed that lecturers had pedagogical views while students tended to concentrate on surface attributes such as appearance. Students perceived instructional materials containing visual representations as most accessible. This has two implications for the professional development of computing lecturers designing instructional materials. First, lecturers need to appreciate the differences between expert and novice views of accessibility and how students will engage with the materials. Second, lecturers need to understand that learners perceive instructional materials containing visual representations as more accessible compared to "text only" versions. Hence greater use of these may enable students to engage more readily in learning. Given that print is the ubiquitous teaching medium this is likely to have implications for students and lecturers in other disciplines.