Pieter Adriaan Jacobus "Piet" Moojen (26 June 1879 - 1 April 1955) was a Netherlands-Indies architect, painter and writer. He studied architecture and painting in Antwerp. He lived and worked in the Dutch East Indies from 1903 to 1929. He was one of the first architects to implement Modernism in the Dutch East Indies. Moojen became widely known for his work on the Dutch entry at the Paris Colonial Exposition in 1931. He was active as an architect between 1909 and 1931.