Natalie Allyn Sleeth (née Wakeley) (October 29, 1930 – March 21, 1992) was an American composer.

Sleeth was born in Evanston, Illinois. In 1934, she began to study the piano at the early age of four. Later in her life, she received an Academic major in music and a BA in music theory at Wellesley College in Massachusetts. She married a Professor of Homiletics, Reverend Ronald E. Sleeth.

One of her best-known anthems for choir is entitled "Joy in the Morning" and was written for the West Virginia Wesleyan College concert chorale on the occasion of her husband's inauguration as the president of West Virginia Wesleyan College in 1977.

Another favorite, sung widely in the United Church of Canada is "In the Bulb There is a Flower." This was composed as an anthem and dedicated to Ronald, who was diagnosed with cancer very soon after its composition. It was written for the Pasadena Community Church, St. Petersburg FL, conducted by C. Frederick Harrison, and first performed by their choirs in March 1985. It was also performed at Ronald's funeral, the only song of hers to be performed for that occasion at his request. It appears as hymn #703 in the United Church of Canada hymnal, Voices United (Toronto: The United Church Publishing House, 1996). It also appears as hymn #707 under the title "Hymn of Promise" in the United Methodist Hymnal (Nashville, TN: The United Methodist Publishing House, 1989).