This study aims to 1) explore the listening challenges of high- and low-proficiency EFL accounting undergraduates, 2) compare listening challenges and listening strategies between high- and low-proficiency learners and 3) investigate the effectiveness of mobile-assisted language learning (MALL) in developing EFL-listening skills. The participants in this study consisted of 84 fourth-year accounting students from Rajamangala University of Technology Lanna, Chiang Mai, Thailand, who had enrolled in a course called English Listening and Speaking for Business Communication. They were divided into two groups depending on their ability levels (high and low proficiency), based on Kelley's 27% criterion-referenced measurement theory. Each group consisted of 23 participants. The research instruments included 1) a listening-comprehension test used for the pre-test and post-test to determine whether the participants had high or low proficiency and compare the effect of MALL, 2) a questionnaire on listening challenges and the utilisation of listening strategies, 3) a semi-structured interview and 4) a MALL activity plan. Data analysis included the calculation of means, standard deviations, percentages and t-tests. The findings revealed a statistically significant difference between the two groups regarding listening challenges; however, there was no statistically significant difference with regard to listening strategies. Concerning MALL, which was applied to both groups, a statistically significant difference was found in the post-test scores at 0.05. In other words, both high- and low-proficiency learners showed improved performance after the empowering strategies created with MALL.