The “environmental state” is an established concept in environmental politics that describes states with a considerable capacity to address environmental issues with new institutions and policies. At the Rio Earth Summit in 1992, the environmental discourse joined forces with the development discourse, politically facilitating the paradigm of sustainable development. Agenda 21 and the 2030 Agenda both call upon states to adapt their governance structures and policies to this new paradigm, for instance, through integrative national strategies for sustainable development and sustainability councils. The literature is undecided on whether sustainable development can be addressed within the environmental state or if it would be more adequate to speak of a “sustainability state” in its own right. After reviewing the literature, this article argues that the sustainability state is not just a development stage of the environmental state but that it is institutionally layered on other state functions, going clearly beyond – but not replacing – the environmental state. However, this layering may result in a sustainability state that is decoupled from other state functions served through differing structures, decisions, and measures. This article offers a descriptive-analytical conceptualization of the sustainability state and develops formal indicators to operationalize it. It analyzes how new administrative and political, regulatory and policy, financial, and knowledge structures can address different governance principles for sustainable development. All indicators are briefly illustrated with empirical examples from Germany or other countries. According to a preliminary assessment, Germany is considered an example of an emerging, yet possibly partially decoupled, sustainability state.