The article presents an analysis of approaches to the content of the concept of sustainable development and methods for its assessment. The relevance of the research topic is justified by the trends of the spread of a green economy. These trends have been formed, among other things, taking into account the Sustainable Development Goals adopted by the United Nations (UN). Achieving these goals has been identified as a key idea of public administration in many countries. However, in practice, the shift towards a green economy has provoked the emergence of an energy crisis. Under the current conditions, it is important to understand the concept of sustainable development and create an adequate methodology for its assessment. The purpose of the presented study is to examine approaches to assessing sustainable development and testing the proposed methodology for its assessment on the example of a particular region for the period 2010-2019. The study substantiates the allocation of such elements of sustainable development as economic, social, and environmental sustainability; the factors and indicators that determine them have been analyzed. A brief description of the existing methods for assessing sustainable development is presented. The expediency of creating a methodology for assessing sustainable development, not overloaded with indicators, has been proved. Indicators for assessing seventeen basic blocks in the context of the UN Sustainable Development Goals have been formed and justified. The application of the method of standard deviations is proposed. The difference of this method is the use of the best indicators for the assessment period as base values. It appears that such an approach will make it possible to level the differences in the assessed socio-ecological systems. The results obtained have made it possible to identify problem areas in the sustainable development of the region under study, to visualize and characterize the directions of its development. The findings of the study can be used as an information base in the development of programs for the socio-economic development of the territory.