August Bendix Christofer Nielsen (7 May 1877 – 1956) was a Norwegian architect.
He was born in Vik, Somna as a son of politician Sivert Nielsen (1823–1904) and Jonethe Cornelia Falck Heide (1833–1927). He received the name Bendix from his maternal grandfather. In 1910 he married physician's daughter Ella Hassel, who was a sister of Odd Hassel.
Nielsen attended Trondhjem Technical School from 1893 to 1897, and spent the next years as an assistant of architects such as Andreas Bugge, Heinrich Jurgensen, Bredo Greve and Ingvar Hjorth. He started his own architect's firm in Kristiania in 1911. Here, he is best known for the Deichman Library at Schous plass and the entrance portal at Frogner stadion (both 1914). He contributed with Rudolf Emanuel Jacobsen in creating several buildings at Frogner stadion's 1914 Jubilee Exhibition; buildings that were moved later. He also designed villas in Trosterudveien 9 and 7 (both in 1911), Holmenkollveien 61c (1915) and Grakamveien 17 (1922).
From 1918 he partnered with architect Harald Sund. Among their works were Majorstuen Church, Fredrikstad Library (both finished in 1926) and the diocesal seat in Tromso (1924). From 1920 to 1947 Nielsen was the director of regulation in Aker municipality. He was also a member of Aker municipal council from 1919 to 1922. He also led the work of regulating Narvik city.
He was decorated with the King's Medal of Merit in gold. He died in 1956.