Armas Lindgren (1874–1929) was one of the most significant Finnish architects of the art nouveau period.
Lindgren studied architecture at the Polytechnical School of Helsinki with Eliel Saarinen, Herman Gesellius and Wivi Lönn, who became his close collaborators. Together with Saarinen and Gesellius (Gesellius Lindgren Saarinen office), he designed several iconic art nouveau buildings in the turn of the 20th century, i.e. National Museum in Helsinki and their countryside atelier home Hvitträsk in Kirkkonummi. New Student House in Helsinki and Estonia Theatre in Tallinn are his most famous collaborative works with Wivi Lönn. Later in his career, he specialised in sacral architecture.
Aside from the architectural practice, Lindgren worked as a teacher specialised in the history of architecture. He taught students of architecture at the Institute of Technology until his death in 1929.