Sustainability is most often defined in terms of three dimensions: environmental, economic, and social. In legislative acts, environmental sustainability is often pursued directly, whereas the other two are pursued indirectly or not at all, depending on which definition of sustainability is used as a point of departure. This study includes a literature review about "sustainability" as a concept and in particular a case study about the use of this concept in Finnish legislation and preparatory materials. The aim is to establish what type of conceptualization of sustainability is used in Finnish law drafting and what types of roles the different sustainability dimensions have in the preparatory materials that are employed. What emerges is that sustainability seems to be too unclear a goal to be directly pursued in all its dimensions through legislation. Instead of incorporating sustainability, in general terms, as the object of every legislative act, it is recommended that separate policy goals that promote particular aspects of sustainability should be pursued with specific individual laws.