Active learning is recognized as an instructional approach that engages students in active participation and encourages them to reflect on the learning process. This research study aimed to investigate the effectiveness of implementing active learning in the "English at Work" course and to explore EFL undergraduate students' attitudes towards the active learning lessons. A one-group pre-test-post-test design was employed in this research, involving 67 EFL undergraduate students enrolled in the "English at Work" course during the second semester of the academic year 2021. Upon the study's commencement, the "English at Work" test was administered as a pre-test. This was followed by a post-test and the completion of questionnaires at the course's conclusion. Additionally, 12 students were randomly selected to participate in semi-structured interviews. Both quantitative and qualitative analyses were conducted on the collected data. The findings indicated that the lessons developed based on the active learning conceptual model had a positive impact on students' English language proficiency and their attitudes towards learning English. The difference in the mean scores of the pre-test and post-test demonstrated significant improvements in students' English language acquisition. Furthermore, the implementation of active learning lessons, coupled with a variety of engaging activities, fostered positive attitudes among students, enhancing their attention, motivation, and participation in the classroom.