Since the United Nations Conference on Environment and Development in 1992 in Rio de Janeiro, sustainable development became an important issue. Sustainable development often focuses on a single sector or parameter such as tourism, energy supply, water management, different aspects of nature conservation, or economy. In this paper, we provide a comprehensive picture of the development of a region since the Middle Ages and discuss whether this development can be evaluated as socially, economically and ecologically sustainable. We carried out a combined qualitative–quantitative assessment where we use quantitative data and indicators when available, as well as literature sources and expert knowledge from the region for a qualitative assessment. We judge that generally a sustainable development in the Allgäu region can be found, although also some critical points and contentious issues exist. An overall good economic and income situation for most people, the good ecological conditions and rich biodiversity, the relatively well-established social structure, as well as the identity of the people with the region and comparatively low social discrepancy, can be positively stated. In contrast, different actual and future threats exist such as new or planned infrastructure, increasing traffic or tourism activities in certain areas that degrade habitats and reduce species richness, intensification of agriculture in certain areas, but also abandonment of agriculture in other areas, loss of traditions and customs, and declining numbers of smallholders. The objective for the region would be to minimise these negative impacts and reinforce positive trends to assure the sustainable development of the Allgäu.