Alfred Joyce Kilmer (December 6, 1886 – July 30, 1918) was an American journalist, poet, literary critic, lecturer and editor. Though a prolific poet whose works celebrated the common beauty of the natural world as well as his religious faith, Kilmer is remembered most for a poem entitled Trees (1913), which was published in the collection Trees and Other Poems in 1914. While most of his works are unknown, a select few of his poems remain popular and are published frequently in anthologies. Several critics, both Kilmer's contemporaries and modern scholars, disparaged Kilmer's work as being too simple, overly sentimental, and that his style was far too traditional, even archaic.

At the time of his deployment to Europe during the first World War (1914–1918), Kilmer was considered the leading American Catholic poet and lecturer of his generation, whom critics often compared to British contemporaries G. K. Chesterton (1874–1936) and Hilaire Belloc (1870–1953). A sergeant in the 165th U.S. Infantry Regiment, Kilmer was killed at the Second Battle of Marne in 1918 at the age of 31.

Kilmer was born on December 6, 1886 in New Brunswick, New Jersey, the fourth and youngest child of Annie Ellen Kilburn (1849–1932) and Dr. Frederick Barnett Kilmer (1851–1934), a physician and analytical chemist employed by the Johnson and Johnson Company and inventor of the company's baby powder. Joyce was named Alfred Joyce Kilmer after Alfred R. Taylor, the curate; and the Rev. Dr. Elisha Brooks Joyce (1857–1926), the rector of Christ Church, the oldest Episcopal parish in New Brunswick, where the Kilmer family were parishioners. Rector Joyce, who served the parish from 1883 to 1916, baptised the young Kilmer. Kilmer's birthplace in New Brunswick, where the Kilmer family lived from 1886 to 1892, is still standing, and houses a small museum to Kilmer, as well as a few Middlesex County government offices.