This study investigates the effectiveness of using songs to enhance students' understanding of idiomatic expressions. A quantitative approach was employed as the research methodology, involving 52 students from grade XII IA 3 and XII IA 4 at SMA Negeri 4 Banda Aceh, divided into experimental and control groups. Pre-test and post-test were used as research instruments to collect data. The test formula used to distinguish between these situations was based on the theory proposed by Arikunto (2006), and t-test tables were used to interpret the t data. The findings indicate that the mean post-test score of the experimental class (XII IA 4) significantly increased from 70.76 (pre-test) to 77.94, while the control class (XII IA 3) showed a slight increase from 57.48 to 59.25. This demonstrates that the use of songs has a significant positive impact on students' understanding of idiomatic expressions. Additionally, the use of songs contributes to the improvement of students' vocabulary mastery, as evidenced by the increase in post-test scores. Lastly, the effectiveness of using songs in English teaching was confirmed by the significant increase in post-test scores in the experimental class. Therefore, it can be concluded that using songs in English language learning not only helps improve students' understanding of idiomatic expressions but also enhances their vocabulary proficiency and the overall effectiveness of English teaching.