The purpose of this study was to explore whether students’ vocabulary learning can be improved via mobile apps and to further enhance their TOEIC scores. Seventy English as a Foreign Language (EFL) senior high school students in Taiwan were recruited. TOEIC tests were used for pre-and post-testing to gather quantitative data. Qualitative data were collected from classroom observations and interviews. The results indicated that there was no significant difference in TOEIC scores between the experimental and the control group. However, students’ attitudes towards the app were positive and believed that it helped improve their vocabulary learning for the TOEIC exam.