Oeko-Institut is the oldest of the Ecornet institutes and one of Europe's leading independent research and consulting institutions working for a sustainable future. Founded in 1977 with a focus on nuclear energy issues, the institute was one of the first to work on the energy transition. Since then, the institute develops principles and strategies for realising the vision of sustainable development globally, nationally and locally.

Based on value-oriented research, the institute provides consultancy for decision-makers in politics, industry and civil society, showing them ways of tackling the environmental challenges we face in an age of rapid social change and globalisation. The experts draw upon a broad array of scientific and research methods and also employ a transdisciplinary approach in their work. 

The Oeko-Institut comprises two operational sections: a non-profit association (Oeko-Institut e.V.) and a limited company (Oeko-Institut Consult GmbH). The limited company is a wholly owned subsidiary of the association.