This study investigated the impact of mobile-assisted language learning on mastering receptive and productive vocabulary knowledge by Iranian EFL learners. The sample of this study included 140 male and female learners from Andisheh Language Institute, Langroud, Iran. Following a Quick Placement Test, 100 intermediate learners were randomly divided into two groups of 50 to conduct the research. Then the treatment began, the experimental group received Beelinguapp as an educational app, whereas the control group used paper word cards. Finally, learners in both groups were given a posttest of CAT and VKS to see if there were any differences in receptive and productive vocabulary knowledge between the experimental and control groups. The data were statistically analyzed using Paired sample t-test, independent sample t-test, ANCOVA, Wilcoxon signed, and Mann Whitney tests. The findings revealed that there is a significant difference between the experimental group and the control group in terms of receptive vocabulary knowledge in the post-test. That is, the participants in the experimental group outperformed those in the control group in receptive vocabulary knowledge. It was also observed that there is no difference between using mobile applications and paper word cards in terms of productive vocabulary knowledge. Pedagogical implications for integrating technology tools in enhancing learners’ vocabulary knowledge are discussed. Manuscript profile