Albert Waldemar Hansteen (25 May 1857 - 4 May 1921) was a Norwegian architect.
Born in Christiania, he worked mainly in his hometown and Skien. He shared responsibility for the Norwegian contribution to the 1893 World's Columbian Exposition in Chicago.
He is most associated with his work on Tostrup Yard (Tostrupgården), a business premises on Karl Johans Gate in Oslo. The structure was designed by architects Christian Fürst, Torolf Prytz, and Waldemar Hansteen and built between 1896-1898. The five story building was one of the oldest in Norway with load-bearing structures in steel. It was also among the first to have an elevator and use electric lighting.
He also oversaw the erection of Gol stave church at Bygdøy, today a part of the Norwegian Museum of Cultural History. His work included the main office of the former Central Bank of Norway (1912-1922, with Henrik Bull), as well as the headquarters of the former Fellesbanken and Sparebanken NOR.