The National Library of Sweden Kungliga Biblioteket has been assigned by the Swedish government to establish resource libraries for the Swedish national minorities. The library of the Finnish Institute in Stockholm is the resource library for the national minority Swedish Finns (also known as Sweden Finns) and the national minority language Finnish. This study examines how a collaboration between the Finnish Institute’s Library and public libraries can support the public libraries in their efforts to pay specific attention to, protect and promote the national minority Swedish Finns and the Finnish language, according to the Swedish Library Act and the Act on National Minorities and Minority Languages and Sweden’s minority policy goals. The theories guiding the study are R. Putnam’s theory of social capital and A. Vårheim’s and R. Audunson’s et. al. theories of public libraries as places creating social capital. The data was collected through qualitative interviews with seven librarians, representing both the Finnish Institute's Library and four public libraries in designated municipality level administrative areas for Finnish. The results show that public libraries could enhance their services and increase social capital of the minority group by cooperating with the Finnish Institute’s Library and make use of its resources and knowledge of the target group. This could support public libraries in paying more attention to children, young people, elderly people and also those in need of Finnish language revitalisation. Though the public libraries participating in this study had less cooperation with the resource library than expected, they’ve got much support from their municipalities and were more active in their library services for the Swedish Finns than many other public libraries in Sweden.