This article gives examples of mobile vocabulary apps (MVAs) that can be downloaded from the Google Play or Apple App Stores and used as extension activities or a supplement to in-class vocabulary instruction in EFL such as English word study, advanced English vocabulary, test your English vocabulary, English vocabulary level I, II & III, 1000 TOEFL words and others. There are also mobile dictionary apps, graded vocabulary tests for assessing vocabulary knowledge and skills and vocabulary trainers for the TOEFL and IELTS test vocabulary. In addition, the article gives guidelines for searching for, selecting, and using MVAs, the phases of teaching with MVAs and the instructor's role. The instructor can help the students find and download relevant MVAs, give pre-questions, and follow the students up to make sure they are making the best use of them. Recommendations for using MVAs with EFL freshman students are given.