Recognizing the urgent need for sustainability, we argue that to move beyond the rhetoric and to actually realize sustainable development, it must be considered as a decision-making strategy. We demonstrate that sustainability assessment and sustainability indicators can be powerful decision-supporting tools that foster sustainable development by addressing three sustainability decision-making challenges: interpretation, information-structuring, and influence. Particularly, since the 1990s many substantial and often promising sustainability assessment and sustainability indicators efforts are made. However, better practices and a broader shared understanding are still required. We aim to contribute to that objective by adopting a theoretical perspective that frames SA and SI in the context of sustainable development as a decision-making strategy and that introduces both fields along several essential aspects in a structured and comparable manner.