Ernest A. Lyon (October 22, 1860 – July 17, 1938) was an African-American minister, educator and diplomat.

Lyon was born on October 22, 1860, in on the coast of Belize, British Honduras to Emmanuel Lyon and Ann F. Bending. As a child, Lyon attended an English school in Belize. His father died when he was young. Lyon "became a Christian by experience October 24, 1875."

Lyon immigrated to the United States in mid 1870s to increase his education opportunities. For three years he attended the Gilbert Industrial Institute in La Teche, Louisiana. In 1880, Lyon attended Straight University. From 1881 to 1883, he attended the Gilbert Seminary while serving as the pastor of the Methodist Episcopal Church, Baldwin, later called Winston. It was here that he met his first wife, Abbie J. Wright who reluctantly married Lyon in a wedding officiated by Rev. W.D. Godman, the president of Gilbert Seminary.

Lyon graduated with A.B. degree in the classics from New Orleans University in 1888. He later earned an A.M. degree in theology from Union Theological Seminary. Lyon has a D.D. degree from Wiley College and a L.L.D from University of Liberia.

Lyon joined the Louisiana Conference of the Methodist Episcopal Church in 1882. The next year, in 1883, Lyon became the first charge in La Teche. In 1894, he "was appointed Sunday School Agent of the Louisiana Conference." He also served as the Conference statistical secretary and the reserve delegate of the General conference for several years. He was an editor of the Sunday school column in the Southwestern Christian Advocate. By 1895, Lyon was the "special agent of the Freedman's Aid and Southern Educational Society." Later he served as a pastor in multiple churches in New Orleans including the Mallalieu Methodist Episcopal Church in 1886, the Thompson Church in 1889, and the Simpson Church in 1891. In 1896, he was the pastor of St. Mark's Church in New York City. Lyon was a member of the New York City Missionary and Church Extension Society. While pastor of St. Mark's Church, Lyon was the only African American among 300 members of the New York Conference.

As an ardent Republican, Lyon was appointed as an auxiliary member of the Republican National Committee in 1884. In this role, all matters about the "colored vote" in the Eastern United States were referred to him. In 1890, Lyon was appointed by the RNC as a member of the advisory board.

In 1901, Lyon was the pastor of the John Wesley Methodist Episcopal Church in Baltimore, Maryland. That same year he worked as the professor of church history at Morgan College. He was among the founders of the Maryland Industrial and Agricultural Institute for Colored Youths, a school for African-American youth in North Laurel, Maryland. He later served as the first president of the school.

The civil rights leader Booker T. Washington recommended Lyon to President Theodore Roosevelt, who appointed him U.S. Minister and Consul General to Liberia in 1903. He served in this capacity until 1910. Following his diplomatic service, he returned to Baltimore to become the minister of Ames Methodist Episcopal Church.