Problem-Based Learning (PBL) is an alternative pedagogical model that differs considerably from the traditional chalk and talk didactic approach. However, to date there are still very few studies into its operation and effectiveness especially in the field of language learning. This study focuses on PBL in English for Specific Purposes (ESP) course at a higher learning institution and thus extends our understanding of PBL in general and in the context of second language learning in particular. This ethnographic approach case study research investigated an ESP classroom over a semester in University Technology Tun Hussein Onn Malaysia (UTHM) to determine (i) students' and learners' perceptions and experiences of PBL, (ii) what students learn and how they learn; the learning process and (iii) the impact of PBL on the students' English language use and development. Data were collected through classroom observations, field notes, lecturer and student interviews, reflective journals and course documents. The data were transcribed using Transana, a qualitative video analysis software, then coded and analysed for emerging themes. The findings reveal that the PBL approach is well received by the ESP lecturers in the study context; it is seen to offer advantages in terms of student motivation, attitude, confidence, engagement; (MACE) and their independent self-directed learning and team-working (IT) skills; increased the English usage among the students under study which in turn have a positive impact on their language development. Furthermore, the findings suggest that the MACE-IT model conceptualises the potential of PBL as an educational initiative for change in the classroom culture which also assists language learning.