This study examined the effectiveness of teaching vocabulary words to EFL students in semantically related sets versus unrelated sets. Fifty-seven EFL students between the ages of 15-18 participated in weekly vocabulary lessons over 5 weeks that presented words in either a related or unrelated fashion. Post-tests found that students acquired words in the unrelated sets more than those in the related sets. However, the study noted a follow up test was needed to determine long-term retention of the words. It concluded that teachers should use a variety of strategies tailored to their students, and not to avoid related word sets but combine different approaches.