The concept of sustainable cities is based on a development paradigm that recognizes the rapid growth of the urban population and makes an important contribution to the formation of the urban plan. Sustainable urban development is a prerequisite for creating a sustainable city. A sustainable and smart city consists of innovative solutions. This thesis will define what is green growth and green innovation, what is a sustainable, compact and smart city and it will show how certain innovative solutions were introduced in Copenhagen in order to achieve city sustainability. To that extend, an overview of innovations in the context of environmental protection is given. A comparative analysis of the achievement of the objectives of SDG 11 - sustainable cities and sustainable communities in Copenhagen will be carried out in relation to other European cities. The aim of this thesis is to determine whether innovations affect the achievement of sustainable development goals and whether the application of innovative solutions in Copenhagen can contribute to the sustainability of the city. In conclusion, proposals for achieving the goals of sustainable development based on the results achieved by the city of Copenhagen will be presented.