Mobile devices have penetrated all spheres of human activities, including education. Previous research has shown that smartphones are becoming widely used in learning as they can improve knowledge retention and increase student engagement. The purpose of this study was to discuss students’ perception of the use of a mobile application aimed at learning new English vocabulary and phrases and describe its strengths and weaknesses as perceived by the students. In total, 28 university students answered a pen and paper questionnaire survey after experiencing the app during one semester. Overall, the students’ agreement to the positive aspects displayed in the questionnaire prevailed over their disagreement or neutral opinions. The mobile app helped students prepare for the final achievement test, learning was accessible from anywhere and at any time, students appreciated the corrective feedback and would opt for the implementation of the mobile app in other courses taught at the faculty. On the other hand, as the findings indicate, the students reported that the app was not very supportive regarding communication performance; they did not find the teachers’ notifications encouraging and they did not use the pronunciation support much, which was caused by various factors, such as offering students words and phrases without context or not testing all the items in the final credit test. The findings of this study contribute to the existing knowledge of students’ perceptions of the use of mobile apps for learning purposes.