Haavard Martinsen (6 February 1879 – 2 August 1967) was a Norwegian chemist and industrial leader.
He was born in Nedre Eiker to Gustav Martinsen and Johanna Jeremiassen. He graduated as chemist from the University of Dresden in 1902. From 1918 to 1949 he was director of the mill Bjølsen Valsemølle. He served as mayor of Kristiania from 1920 to 1922. He was decorated Knight, First Class of the Order of St. Olav in 1939, was Commander of the French Legion of Honour, Grand Officer of the Order of Orange-Nassau, and was awarded the Order of the British Empire.