Economic growth has several negative consequences for the environment. At first glance, the impact of the environment on the well-being of the population may seem insignificant. Still, several scientific studies demonstrate that the state of the environment has no less impact on the well-being of the population than economic or social factors. This study aimed to assess Ukraine’s environmental well-being in comparison with the member countries of the Organisation for Economic Co-operation and Development. The assessment of environmental well-being is based on indicators from the Organisation for Economic Co-operation and Development Better Life Index and the Environmental Performance Index. Fuzzy set theory is used to research and evaluate environmental well-being. During the study, a fuzzy inference system was constructed, which was used to obtain an assessment of Ukraine’s environmental well-being compared to the Organisation for Economic Co-operation and Development countries. Three indicators were used in the study: air pollution, sanitation and drinking water, and agriculture. Results indicate that compared to the Organisation for Economic Co-operation and Development countries, Ukraine is on the border between medium and high levels of environmental well-being. The research findings are supported by the Environmental Performance Index, where Ukraine ranked 41st out of 180 countries in 2024, climbing 11 positions compared to 2022. Although Ukraine has already demonstrated progress in the Environmental Performance Index in 2024 compared to the 2022 results, it can maintain such a trend only if it knows which specific environmental indicators need improvement. Therefore, the practical value of this research lies in demonstrating the environmental indicators that require improvement