Learning EFL vocabulary is a challenging undertaking, therefore teachers do everything they can to make it easier for their students. The purpose of this study is to determine the efficacy of employing AR apps in increasing English vocabulary acquisition in pupils in preparatory school. The pre-post test control/experimental group design was used in the study. The study sample consisted of 40 first-year pupils from Engineer Muhammad Osama Emara Joint Preparatory School in Egypt, who were separated into two groups: an experimental group and a control group. Pupils in the experimental group used AR applications to acquire vocabulary, whereas students in the control group got regular instruction. A pre-post vocabulary achievement test, a suggested teacher's guide for the text course "New Hello" for first preparatory grade, and an AR application designed for the purpose of the study were among the study's tools. The pupils took pre-post vocabulary achievement test, and the results show that there is a statistically significant difference in mean scores between the experimental and control groups in the pre/post-test of English vocabulary achievement in favor of the experimental group.