This is a brief review of the history of usability and a discussion of usability in developing a computer-based learning program (CBLP). According to ISO 9241, usability is defined as the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use (Bevan, 2001). The main focus of usability in this article is concerned with the user interface and interaction design. To create a usable computer-based learning program, one needs to understand the definition of usability and the goals of usability. Besides achieving usability goals, a usable CBLP should also be able to attain user experience goals. Design principles can be used to develop a CBLP featured with usability. Two design models will be discussed in this review.