The multimedia aspect of the Web creates opportunities for businesses to channel their advertising. Advertising effectiveness is important to the marketers to know if their advertisements have affected their target audience. Among the market segmentation variables, gender has had a deep history in the marketing environment and has been used as a primary segmentation variable. This research examines whether gender difference is a factor in the relationships between online consumer characteristics and banner advertisement effectiveness. The characteristic variables included in this study are: online consumer?s internal flexibility, consumer expectations and consumer involvement. A questionnaire survey was administered with 190 online consumers who were senior students at a university. The study results gave mixed results. In the context of web-based banner ad, gender influences the following relationships: (i) banner ad judgment and attitude towards banner ad, (ii) focus & planning approach and attitude towards banner ad and (iii) consumer expectations and banner ad effectiveness. The study also found that there is no gender difference in other relationships between online consumer characteristics and banner ad effectiveness.