Agriculture is one of the main human activities with direct and indirect effects on the environment. The abandonment of many traditional agricultural practices, mainly for their inability to meet the current requirements of industrial agriculture, has brought to unsustainable agricultural systems characterized by high external energy inputs and by a high fragility to environmental and political shocks. Therefore, sustainable agriculture is nowadays crucial for preserving the environment. Agricultural heritage systems are receiving increasing attention at the international level, as testified by the establishment of the Globally Important Agricultural Heritage Systems (GIAHS) Programme by the Food and Agriculture Organization (FAO). The aim of the GIAHS Programme is, in fact, to identify and safeguard agro-silvo-pastoral systems resulting from the co-existence between humans and nature, which survived using traditional techniques are still providing many ecosystem services, while maintaining magnificent landscapes, wild and agricultural biodiversity, ancestral knowledge, and strong cultural and social values. These systems, based on sustainable practices, are still able to provide food and livelihood security, resources and services to local communities, but are also examples of adaptation and mitigation to climate change and to different and often difficult environmental conditions, as well as models of resilience and sustainability. In 2018 the Italian Agency for Development Cooperation (AICS), together with the Department of Agriculture, Food, Environment and Forestry (DAGRI) of the University of Florence, developed a project called "GIAHS Building Capacity", aimed at identifying agricultural heritage sites in different parts of the world. This Special Issue collects the results of investigations carried out in thirteen sites in Central and South America, Europe, Africa and Asia offering a wide an coherent perspective on agricultural heritage systems across the world. The papers included in the Special Issue proved that agricultural heritage systems, despite some vulnerabilities mainly due to socio-economic causes rather than to environmental ones, still provide different ecosystem services to local communities, including: food and byproducts supply, soil erosion protection, hydrogeological risk and deforestation defense, agrobiodiversity and biodiversity conservation, cultural landscape preservation, agro-tourism; at the same time they can be important for transmitting traditional knowledge to new generations and for the local identity. The GIAHS programme can play a key role in preserving traditional agricultural systems, and their related agrobiodiversity and ecosystem services, both in developing and developed countries. In fact, its aim is not limited to the conservation of these systems, but the whole Programme is based on the concept of dynamic conservation, as sustainable innovations are needed for the preservation of agricultural heritage systems and, therefore, for the future of rural areas and of rural communities. The research is part of the activities promoted by the UNESCO Chair on Agricultural Heritage Landscapes established at the University of Florence. [ABSTRACT FROM AUTHOR]