Corporate social responsibility (CSR) has become a popular trend in business for sustainable development in developed countries yet evolved in developing countries, particularly in Vietnam. Studies about CSR practices in Vietnam remain scarce, especially in small-and medium-scaled enterprises (SMEs). Most of the enterprises do not have sufficient understandings of CSR aspects, but a variety of perceptions due to different business contexts. This study aims at examining the perceptions and practices of CSR implemented by SMEs in Vietnam. Theoretical framework provides a debate of CSR’s pyramid in developed countries which are established by dynamics of economic, legal, ethical, and philanthropic responsibilities. It argues that CSR practices in developing countries are formed by a shift of economic and legal responsibilities, which found dominant in developed countries, into philanthropic responsibilities due to country-specific contextual determinants. The study also looks at environmental responsibilities, which has been considered an important aspect that emerged in the past recent year, and how it is incorporated in CSR practices by SMEs in the country. The study employs Qualitative research method that focuses on Grounded theory to theorize the CSR phenomena based on semi-structured interviews with enterprise’representatives, reports, websites, and researcher’s personal observation. The study findings suggest that understandings and practices of CSR in Vietnam are similar to such dimensions in developed countries, which are driven by economic and legal aspects and are influenced by external environment such as market segments where SMEs sell their products. Meanwhile, environmental responsibilities are found evolving in CSR practices as a result of government regulations and market requirements. The study concludes some implications and recommendations for promoting CSR in small and medium-scaled business organizations in the country towards sustainability.