Nikulás Ottenson (born Nikulás Össursson 18 November 1867 at Hvallátrar near Látrabjarg in Rauðasandshreppur on Barðaströnd; died 15 August 1955, Gysler Nursing Home, Winnipeg) was an Icelandic scholar, who spent most of his life in Canada. His book collection is now the Nikulás Ottenson Collection of Icelandic Books and Manuscripts, Special Collections, Milton S. Eisenhower Library, The Johns Hopkins University.