Human-computer interaction problems have been approached by design practitioners and researchers for a few decades now. Usability is an established quality attribute that is used to assess how easy user interfaces are to use. Websites have been determined to benefit from such assessment, and responsive web design (RWD) is a fairly new approach to web design where usability problems have been recognised, and where usability focused research has been carried out. While usability testing can be used to determine how easy a RWD website is to use, it does not provide a detailed psychological model that tells the designer how to design RWD websites that are easy to use. Discoverability is a psychological model within the field of design in general, that can be implemented by designers who want to achieve a good design. No previous research has been carried out with the purpose of exploring how discoverability can be used to improve the usability of a RWD website, and the author of this thesis suggests that there is value in conducting such research, because it has the potential to provide new insight into how RWD websites can be designed in way that makes them easier to use. This thesis approaches the question by conducting a usability test on a RWD website, and uses the results of the test as a foundation for a suggested discoverability focused approach to improving the usability of the RWD website.