The authors believe that the adoption of virtual worlds is suitable for electronic government applications as it can increase the capillarity of public services, facilitate the access to government services and provide citizens with a natural and immersive experience. They present a Government Virtual Institution Model (GVI) for the provision of public services that satisfies relevant issues such as: adaptability to different citizen education level and to heterogeneous government systems; alignment with government services requirements related to security, privacy, reliability and scalability; and government interoperability requirements. The model of the GVI, the government services and the information flow across the GVI are formally described using the JamSession platform (Correa da Silva, 2011). The model of the GVI uses an architecture based on governmental patterns (including ontologies for information representation) to deal with the connections to the governmental systems, and 3D virtual world simulation systems to interact with citizens. (Contains 6 figures.)