William Allen Trimble (April 4, 1786 – December 13, 1821) was a Democratic-Republican politician from Ohio. He served in the United States Senate. Trimble was born in Woodford, Kentucky, the son of James and Jane (Allen) Trimble. He graduated from Transylvania College and was admitted to the bar in 1811. He briefly practiced law in Highland County, Ohio from 1811-1812. In the subsequent years he served in a variety of capacities, mostly with the Ohio militia and the U.S. Army in campaigns against the Pottawatomie Indians. He was a major of the Ohio Volunteers in 1812 and major of the Twenty-sixth United States Infantry in 1813. He was promoted to lieutenant colonel in 1814 and then to lieutenant colonel of the First United States Infantry in 1814. He was transferred to the Eighth United States Infantry in 1815 and served there until his resignation in 1819, following his election to the U.S. Senate for the term beginning in 1819. William Trimble served in the Senate until his death two years later. He died in Washington, D.C. on December 13, 1821 and is interred in the Congressional Cemetery in Washington, D.C.