As a regional library, it is obliged to fulfil certain functions, carried out in conjunction with the Gottfried Wilhelm Leibniz Bibliothek in Hanover (which is also the Niedersächsische Landesbibliothek, or State Library of Lower Saxony) and the Landesbibliothek Oldenburg. In accordance with press legislation in Lower Saxony, the obligation on publishers and printers to deposit a copy of a published work is mainly the responsibility of the Niedersächsische Landesbibliothek in Hanover. The function of each state library is set out in detail in target agreements between the state libraries and the Niedersächsisches Ministerium für Wissenschaft und Kultur (Lower Saxony Ministry of Science and Culture, MWK).

In addition, the Herzog August Bibliothek is an active member of the consortium of regional libraries within section 4 (scholarly research libraries) of the Deutsche Bibliotheksverband (German Library Association, dbv). Current activities include efforts to create a Verteilte Digitale Landesbibliothek (Distributed Digital State Library, VDL), which will initially contain digitised versions of historical maps and manuscripts from Lower Saxony’s three state libraries.

There is an inherent tension in the work undertaken by the library – on the one hand, it aspires to be one of the most distinguished research libraries, while, on the other, its effectiveness is comparatively restricted as a regional library – and this has its difficulties, as illustrated in the following statement by the former director of the library, Erhart Kästner (1904–1974, director 1950–1968): ‘The worst thing that could happen is if the Wolfenbüttel Library were to try to become a state library like any other.’