A stenolaemate bryozoan fauna from the Late Ordovician (Katian) Mjøsa Formation of Bergevika (Helgøya, Mjøsa), southern Norway contains nine species. Seven species belong to the Order Trepostomata: Esthoniopora subsphaerica (Bassler, 1911), Hallopora gracilens Bassler, 1927, Diazipora parva (Bassler, 1911), Hemiphragma batheri Bassler, 1911, Eridotrypa suecica Brood, 1978, Trematopora brutoni sp. nov. and Anaphragma latviense Pushkin, 1976. Two species belong to the Suborder Ptilodictyina of the Order Cryptostomata: Trigonodictya cyclostomoides (Eichwald, 1855) and Astrovidictya sparsa Lavrentjeva in Gorjunova & Lavrentjeva, 1993. The bryozoan faunal association is similar to that found in equivalent Baltoscandian units elsewhere, but rather different from Laurentian units. Their known biostratigraphic range is generally Late Ordovician.