Abstract: This study investigated the role of English language clubs and extracurricular activities in fostering language proficiency at Vietnamese universities, addressing a significant research gap in understanding the effectiveness of informal language learning environments in the Vietnamese higher education context. The research aimed to examine the impact of English clubs on language proficiency, analyze the effectiveness of various extracurricular activities, and identify best practices in club management. Using a qualitative approach, the study conducted a multiple case study of three universities across Vietnam, involving 45 participants (30 students, 9 club organizers, and 6 faculty advisors).