Sustainability, a nebulous but attractive concept, poses an essential question for every activity – if it can continue. The concept of sustainability is broad, and it is also often used interchangeably with the concept of sustainable development (SD). These two concepts are analyzed in their interrelations and in relation to the concepts of the green economy (GE) and green growth (GG). The aim of the work is to define and clarify the strengths, weaknesses, opportunities, and threats to the concept of SD in its interrelation with sustainability. The focus is also on the possibilities of their practical application, with the aim of sustaining or increasing wellbeing and quality of life within ecological limits. The concepts of SD and sustainability are regarded as fundamental notions and as a basic philosophy in relation to which the remaining concepts are analysed. Efforts were also made to clarify the most crucial relations of the transformation discourses to SD. The use of the concepts as a basic philosophy, including the balance of the three pillars of sustainability/SD, are the main strengths identified. Important opportunities arise from exploiting these strengths and moving closer towards the aims of SD, which include quality of life and wellbeing. With the goal of sustaining sources of wellbeing for people, opportunities for crucial practical applications and methods of measurement of SD, including the development of sustainability science, are identified.