This paper is intended to evaluate intermediary role of SCI in the relationship between supply chain management practices (SCMP) and supply chain performance (SCP) and, at the same time, to examine the regulatory role of firm size and transformational leadership in this relationship. The research is conducted on 536 Vietnamese textile and garment enterprises and the results show that SCI had a complete intermediary role in the relationship between SCMP and SCP. Additionally, Size and Transformational leadership also play statistically significant regulatory role in the relationships between SCMP and SCI as well as between SCMP and SCP. Accordingly, it is recommended that enterprises should implement SCMP well to improve the effectiveness of SCI and SCMP, contributing to sustainable development and ensuring requirements of global supply chains.