Blended learning, integrating traditional and online instruction, has emerged as a significant approach to enhancing English proficiency (listening, speaking, reading, writing) among non-native university students. This study conducted a PRISMA 2020-guided systematic review of 52 articles (2020-2024) from Web of Science, Scopus, EBSCOhost, and ERIC, with 30 meeting MMAT quality criteria. Using the PICO framework, it analyzed blended learning's impact on language skills. Findings indicated notable improvements across all four competencies, attributed to methods like timely feedback, task/project-based learning, and self-paced modules, alongside strategies such as flipped classrooms, multimodal resources, mobile technologies, and collaborative activities. These approaches enhanced flexibility, interactivity, and personalized learning while providing rich resources. The integration of online and offline phases, combined with structured peer/instructor interaction, was critical for skill development. Results underscore blended learning's potential to inform instructional design, policy-making, and quality improvements in higher education language programs, addressing globalization-driven demands for advanced English proficiency.