Nils Ulrik Alfred Sinding-Larsen (5 June 1839 – 28 January 1911) was a Norwegian civil servant, teacher at the Military Academy, journalist and writer.
He was born in Fredrikstad as a son of physician Ole Peter Larsen (1808–1876) and Frederikke Hedevig Sinding (1815–1891). He took the name Sinding-Larsen in 1881. He was a nephew of mining engineer Matthias Wilhelm Sinding, and a first cousin of the three siblings Christian, Otto and Stephan Sinding and another three siblings Ernst Anton Henrik Sinding, Elisabeth Sinding and Gustav Adolf Sinding.
In June 1865 in Arendal he married Elisabeth Lange (1842–1887). She was a sister of Balthazar Lange. They had four notable children; physician Christian Magnus Sinding-Larsen, colonel Birger Fredrik Sinding-Larsen, architect Holger Sinding-Larsen and painter Kristofer Sinding-Larsen. He was a grandfather of architect Knut Martens Sinding-Larsen, architect Kirsten Sinding-Larsen and journalist Henning Sinding-Larsen.
He finished his secondary education in 1855, then graduated with the cand.jur. degree in law in 1863. In his jurist career, he worked in the Ministry of the Army from 1863. In 1877 he became acting auditor for the Norwegian Cavalry and for Akershus garrison. He left these positions in 1901, but also tutored at the Norwegian Military Academy from 1889 to 1905. He was also a secretary for the executive committee of Kristiania city council from 1875 to 31 December 1896. He was also a member and secretary of Christiania Kunstforening.