This study explores junior high school students' perceptions of using Kahoot! for vocabulary learning, guided by two research questions: (1) how do students perceive the use of Kahoot! as a digital learning medium for vocabulary learning, and (2) what challenges do students encounter during its implementation. This study employed a qualitative approach using a case study design. The participants consisted of 32 seventh-grade students who completed questionnaires, while six students representing high-, medium-, and low-achieving groups and one English teacher participated in semi-structured interviews. Data were collected through classroom observations, questionnaires, interviews, and documentation, and were analyzed using thematic analysis, with the questionnaire results used to support and strengthen the qualitative findings. The findings related to the first research question revealed that students generally had positive perceptions of using Kahoot! for vocabulary learning, as the platform enhanced (a) students' motivation, (b) engagement, (c) participation, and (d) vocabulary comprehension through its interactive features, competitive elements, and immediate feedback. For the second research question, the study identified several challenges, namely (a) unstable internet connections, (b) limited response time, (c) unfamiliar vocabulary, and (d) pressure caused by the competitive nature of the game. Overall, Kahoot! proved to be an effective digital learning medium that supports vocabulary learning by promoting active participation and meaningful learning experiences, and despite several technical and learning-related challenges, the platform can be considered an appropriate instructional tool for English vocabulary learning.