Corporate governance is essential for businesses, especially those with complex structures. This research examines the relationship between business group structures, corporate governance, and business performance in Vietnam, providing theoretical insights and practical management recommendations. Analyzing data from over 100 of the largest listed companies on the Vietnam Exchange AllShare, the study used the Fixed Effects Model, Random Effects Model, and Feasible Generalized Least Square estimations to assess the impact of business groups on governance and performance. The study reveals a positive but relatively weak impact of expanding the scale of business groups on the quality of corporate governance and business efficiency. Audit Committees, Independent Directors, and company size positively influence governance quality, while liquidity has a negative impact. Similarly, these factors positively affect business efficiency, whereas financial leverage has an inverse relationship. This research enhances the understanding of how business group structures influence corporate governance and business efficiency in Vietnam. It underscores the importance of good governance principles to improve accountability, transparency, and protect stakeholder interests, highlighting the positive role of certain governance structures in enhancing business efficiency.