Brazil is the world's leading producer and exporter of coffee, one of the country's most important agricultural products. In the national coffee industry, Geographical Indications (GI) for coffee have seen an increase in the number of registrations recognized by the National Institute of Industrial Property (INPI). The GI is a strategy that seeks to organize, protect and valorize specific characteristics of each region, with a tendency to promote development. Although there is scientific evidence of the territorial development promoted as a result of GI registrations, there are still gaps in research on the subject. The problem of this research is anchored in the following question: What is the role of public rural extension and technical assistance services and support organizations in the effectiveness of coffee GIs? The objective is to understand the role of public technical assistance and rural extension services and support organizations in the effectiveness of coffee GIs. To this end, a field study was conducted, supported by a literature review. The awareness-raising and educational process regarding the potential, the process of collective construction, implementation and maintenance of the GI were verified using specific interview scripts for rural producers and support organizations, in three Brazilian states and five already consolidated coffee GI territories. This confirms the importance of public technical assistance and rural extension (ATER, its acronym in Portuguese), not only for the consolidation of a GI, but for sustainable development as a whole. The public ATER is not sufficient to meet the needs of territories that are applying for GI registration or that already have one. It is important to emphasize that extension professionals are valuable as well as their organizations and that human capital is fundamental to this process. It is essential to look for the support network, which proved to be efficient and cooperative in the territories studied. It was noted that the GI does not exclude small farmers due to its rules, but rather the inefficient communication process that leaves doubts that distance small coffee growers from accessing the GI. It is necessary to adopt a dynamic communication that reduces the noise and strengthens the participatory process in the drafting of requirements and decision-making. GI registration in itself does not guarantee development, but it has a great potential and the role of public ATER and support organizations in each territory is fundamental to support the effectiveness of the registry.