With emergence of urbanization and climate change new solutions for maintaining and improving the quality of life in cities are required. Presence of public green urban areas have positive impact on biodiversity, climate, human well-being and air quality. The word ‘green’ means different things to different people. Both environmental and socioeconomic problems are common in cities. Due to the great variety and interpretation of problems, several definitions and approaches have emerged for the term ‘green city’. The authors used literature review to analyse definitions of ‘green city’ and related concepts. The results show that private and public organizations use the word ‘green’ as a reference to environmental performance and sustainability. Green city is a special type of sustainable city, in which the advancement of sustainable development goals is achieved by reducing the environmental impact of the city. A green city is linked to healthy natural environment, healthy people and growing economy. Environmental and economic studies show that investing in sustainable and green urban infrastructure, such as public transportation, energy efficiency of buildings and waste management, could save up to 40% of energy consumption by 2050. Further research directions are linked to applying the concept of circular economy to cities.