Carl Gustav Oskar Aagaard (September 18, 1852 – January 16, 1927) was a Norwegian writer and priest.
His stories were primarily of a religious nature, but he also published later stories that were generally entertaining, but with a strongly emphasized moralizing tendency.
He is also known for his hymns.
Gustav Aagaard was the brother of the author Oscar Aagaard (1855–1936).