Sustainability is a key concept used in many fields today. The concept, which takes its place in the urban planning literature, offers solutions against the negative effects of urbanization and rapid industrialization on societies and the environment. In order to ensure the development of cities in line with the principles of sustainability, it is extremely important to have indicators that will help the development goals to be monitored and evaluated. Today, there are 23 urban sustainability indicators put forward by different countries and organizations in the international arena. The most of these are “United Nations Guide to Urban Indicators” and “European Foundation Urban Sustainability Indicator”. In this study, the criteria in these two basic indicators are discussed and the contributions of urban open-green areas to the urban sustainability targets of the relevant criteria are examined on the basis of "ecological", "economic" and "socio-cultural" headings. The findings revealed that urban open-green spaces are one of the main actor of sustainability