Alongside the increasing concern of the Korean state in preparing for the 4th Industrial Revolution (4IR) era, Korean national (English language) curricula are being reconstructed to educate students about criticality, creativity, communication, and collaboration. Problem-based learning (PBL) is one of the effective pedagogical approaches to facilitate these competencies alongside different disciplines including English language competency. Thus, teachers and teacher educators in Korean English language teaching (ELT) need quality-assured research cases that address PBL-based ELT programmes in the Korean context for their references. In this study, the qualities of research on PBL-based ELT programmes in Korea are systematically reviewed, focusing on aspects of the statement of research purposes, conceptual frameworks of PBL, procedures of PBL application, evaluation of the PBL effects, and revealed limitations, and implications for improvement. Based on the findings, implications for improving research on PBL in Korean ELT are discussed.