The aim of this paper is to classify research, policy priorities, and development objectives in mountainous and less favored areas into a conceptual framework of sustainable rural development. The classification of sustainable development is based on the three main pillars: economic development, environmental conservation, and societal equity. Under the pillar of economic development, the role of agrotourism and the role of mountainous agricultural food products are considered. Under the pillar of environmental conservation, the role of environmental protection and the role of the agricultural landscape maintenance are presented. Under the pillar of societal equity, the contribution of women and the role of young farmers are considered. Finally, the conceptual framework developed is used to classify, analyze, and evaluate the latest research findings from Greece.