In the context of global efforts toward sustainable development, the green transformation of small and medium-sized enterprises (SMEs) has become a critical pathway to achieving environmentally responsible and resource-efficient growth. This study adopts a qualitative research approach to explore how Vietnamese SMEs perceive and implement green transformation strategies and to identify the key drivers and barriers influencing this process. A multiple case study design was employed, involving in-depth semi-structured interviews with 18 participants, including SME managers, environmental officers, and policymakers from six industries: manufacturing, textiles, food processing, construction, logistics, and services. Supplementary data from corporate reports and government documents were analyzed to triangulate findings. Using thematic analysis, the study identifies four major themes shaping the green transformation journey of Vietnamese SMEs: (1) emerging environmental awareness and compliance-driven initiatives; (2) limited access to green technologies and financial resources; (3) institutional and policy gaps; and (4) the growing influence of global supply chain standards and consumer expectations. Although most SMEs have adopted basic green practices, such as waste reduction and energy efficiency, their transition remains partial and fragmented, primarily constrained by cost pressures and the absence of consistent policy incentives. The findings highlight that Vietnam’s green transformation among SMEs is still at an early stage and largely reactive rather than strategic. To foster more profound change, the study recommends stronger governmental support mechanisms, improved access to green finance, and targeted capacity-building programs for SME leaders. This research contributes to the literature on sustainable business development in emerging economies by providing empirical insights into the behavioral and institutional dimensions of green transformation, offering policy recommendations for advancing Vietnam’s transition toward a greener economy.