BACKGROUND AND OBJECTIVES: Environmental guidelines and principles of sustainable development are becoming increasingly popular and are a priority for most business areas. One of the widely developing eco-destinations is green tourism, which is gaining a profitable and priority status, especially for lower middle-income countries. The purpose of the article is to determine the strategic marketing support for the development of green tourism on the example of Ukraine and its regions based on an approach to its assessment in terms of environmental and tourism competitiveness.METHODS: The authors used general scientific and specific methods: comparative, critical and system analysis, synthesis to search and group indicators of ecological and tourism competitiveness. Distance method, ranking, economic and statistical analysis were implemented to analyze the green tourism potential in each region in Ukraine and reveal the leaders and outsiders among them. For the accumulation, processing, visualization of data and forming the matrix of green tourism, based on data for ۲۰۱۵-۲۰۱۹, potential Microsoft Excel, Figma and Canva tools, Harrington scale were applied.FINDINGS: The approach to estimate the green tourism potential based on the ecological and tourism regional competitiveness according to the author’s list of ۳۷ indicators were proposed, the matrixes of green tourism potential of Ukrainian regions in ۲۰۱۹ and ۲۰۲۰ were developed, and strategic marketing support according to sustainable development for green tourism business were proposed. Strategic marketing support of green tourism development in Ukrainian regions was defined based on ecological and marketing strategies.CONCLUSION: The author's approach makes it possible to systematically assess the potential of green tourism using up-to-date statistical information. According to the tourism and environmental competitiveness rating, the regions with the most significant and worst potential were found. The positive dynamics of the development of green tourism in ۲۰۱۹-۲۰۲۰ were revealed. The results are the basis for providing comprehensive environmental and marketing support to ensure sustainable development and gain additional competitive advantages in the green tourism business.