David Lowrey Seymour (December 2, 1803, Wethersfield, Hartford County, Connecticut – October 11, 1867, Lanesborough, Berkshire County, Massachusetts) was an American lawyer and politician from New York.
He graduated from Yale College in 1826, and was a tutor at Yale College from 1828 to 1830. Then he studied law, was admitted to the bar in 1829, and commenced practice in Troy, New York.
He was a member of the New York State Assembly in 1836.
He was District Attorney of Rensselaer County from 1839 to 1842.
Seymour was elected as a Democrat to the 28th United States Congress, holding office from March 4, 1843, to March 3, 1845, and was Chairman of the Committee on Revolutionary Pensions.
Seymour was elected to the 32nd United States Congress, holding office from March 4, 1851, to March 3, 1853, and was Chairman of the Committee on Commerce. Afterwards, he resumed the practice of law.
He was a delegate to the New York State Constitutional Convention of 1867.
He was buried at Mount Ida Cemetery in Troy.
His law partner and son-in-law Charles E. Patterson was Speaker of the New York State Assembly in 1882.