The present study aims to review systematically all the studies of web site usability conducted in the years from 2005 to 2014 in order to present the research trends in usability issues of web sites. Regarding the inclusion criteria 199 studies in total were included in the study. The major findings include that the most frequently addressed usability issue is navigation (excluding general usability issues) most of the studies used user-based Usability Evaluation Methods (UEMs) the most frequently ...