This study investigates the effectiveness of Mobile-Assisted Language Learning (MALL) in enhancing vocabulary acquisition among second language learners. Employing a mixed-methods approach, the research combined quantitative assessments of vocabulary gains with qualitative insights into learner experiences. A sample of 60 intermediate-level learners was divided into an experimental group, which utilized MALL applications (e.g., Duolingo, Quizlet) for eight weeks, and a control group, which engaged in traditional classroom-based instruction. Quantitative data from pre- and post-tests revealed a statistically significant improvement in vocabulary retention within the MALL group, with a moderate effect size (Cohen’s d = 0.45), outperforming the control group. Qualitative analysis of surveys and interviews highlighted key advantages of MALL, including personalized pacing, interactive exercises, instant feedback, and heightened learner motivation. However, challenges such as digital distractions, uneven internet access, and occasional technical barriers were also reported. The findings suggest that MALL serves as a valuable complement to conventional methods, particularly by fostering engagement and autonomy. This study advocates for a blended pedagogical approach that integrates mobile technologies while addressing infrastructural and instructional limitations. Implications for educators, app developers, and policymakers are discussed, alongside recommendations for future research on long-term retention and MALL’s efficacy across diverse learner demographics.