Tourism is considered one of the key economic sectors in Vietnam as it helps to promote the economic development, increase foreign exchange earnings, create jobs, and improve the living standards of local people. So, this study aims to identify factors affecting the competitiveness of Soc Trang ecotourism associated with Khmer culture based on a combination of qualitative and quantitative research methods. Qualitative research was conducted through focus group discussions with experts, and quantitative research was conducted through direct interviews with visitors at ecotourism sites in Soc Trang province. The study involves questionnaire surveys and multivariate data analysis methods (Cronbach’s Alpha test, EFA, CFA, SEM). Research results from 350 respondents demonstrate that all factors have a positive impact on the competitiveness of ecotourism associated with Khmer culture in Soc Trang province. It shows that the competitiveness of ecotourism associated with Khmer culture is influenced by five factors, including: (1) religious ritual customs of the Khmer people; (2) ecotourism infrastructure; (3) traditional festival activities of Khmer people; (4) culinary culture of Khmer people; and (5) folk ritual customs of the Khmer people. From these findings, the study offers some managerial implications to improve the competitiveness of Soc Trang ecotourism associated with Khmer culture.