Advance organizers (AOs) are effective orienting devices in teaching and learning, especially for learners of either low verbal or analytic ability or low prior knowledge. The current study investigated two types of advance organizers graphic and text for students in a fully Web-based undergraduate course of health care ethics. Both the short-term and long-term effects were examined. The results were analyzed for students from the high and low ability subgroups. Although the findings did not demonstrate a statistically significant AO effect, the study suggested students of low ability might be benefited more from using an AO in online learning than those of high ability. Additional qualitative data indicated that students held overwhelmingly positive attitudes toward using AOs, especially the graphic AOs. The findings of this study added new empirical evidence for the use of AOs in Web-based distance education and suggested new directions for further research.