BACKGROUND AND OBJECTIVES: Sustainable tourism is tourism development that has a long-term impact on the environment, society, culture, and the economy for the present and the future. The benefits are felt by local people and tourists. The achievement of this research is the implementation of pro-environmental behavior, which is supported by tourist satisfaction and electronic word of mouth toward sustainable tourism as a form of environmental management policy in West Sumatra. This research aims to show three direct effects: first, the effect of satisfaction and electronic word of mouth on the sustainability of tourism; second, the effect of satisfaction on electronic word of mouth; and third, three moderating effects of pro-environmental behavior, namely, moderating the influence of tourist satisfaction on tourism sustainability, moderating the influence of electronic word of mouth on tourism sustainability, and moderating the influence of satisfaction with electronic word of mouth. METHODS: This study is a quantitative study involving 420 tourists as respondents who visited West Sumatra from January to April 2023. Data analysis used partial least square-structural equation modeling. Structural equation modeling is a field of statistical study that can test a series of relationships that are relatively difficult to measure simultaneously. Partial least square is a component or variant-based structural equation model. FINDINGS: After analyzing the data, it was determined that of the six hypotheses proposed in this study, five were accepted and one was rejected. The rejected hypothesis states that with a significance level of 0.199 > 0.05, pro-environmental behavior does not moderate the effect of electronic word of mouth on the sustainability of tourism. These findings clarify that the impact of electronic word of mouth on the sustainability of tourism is not mitigated by pro-environmental conduct. CONCLUSION: When implementing sustainable tourism, not only economic factors are taken into account but also the preservation of nature and culture. Therefore, the stability of tourism in the future can be guaranteed without adversely impacting the environment.