Annie Maria Barnes (pen name, Cousin Annie; May 28, 1857 – unknown) was a 19th-century American journalist, editor, and author from South Carolina.
At the age of eleven, she wrote an article for the Atlanta Constitution, and at the age of fifteen, she became a regular correspondent of that journal.
In 1887, she began publishing The Acanthus, a juvenile paper issued in the South.
Barnes published novels from 1887 (Some lowly lives and the heights they reached) until at least 1927 (A knight of Carolina).