Claus Nissen Riiber Berg (22 June 1832 – 29 March 1915) was a Norwegian businessperson.
He was born in Aafjorden as a son of bailiff Johannes Berg and Margarethe Riiber.
In 1866 he married Catharine Bygball Lund (1843–1914), daughter of the vogt in Ørlandet.
Their daughter Margrethe married businessman and politician Francis Kjeldsberg,[1][2] and their daughter Astrid married Ingvar Klingenberg.
He was also chairman and honorary member of the gymnastics club Trondhjems TF.