Horatio Collins King (December 22, 1837 – November 15, 1918) was a Union Army soldier who received the Medal of Honor for his actions during the American Civil War.

Born in Portland, Maine, King graduated from Dickinson College in 1858, studied law, and was admitted to the bar in New York City in 1861.

He was the author of The Plymouth Silver Wedding (New York, 1873); The Brooklyn Congregational Council (1876); King's Guide to Regimental Courts-Martial (1882); and edited Proceedings of the Army of the Potomac (1879–'87).

In 1893, when the anti-Chinese Geary Act was ruled constitutional, he protested the law, saying that "from the prejudice manifested against the Chinese, it seems they have no rights here that Americans are bound to respect.

Citation: While serving as a volunteer aide, carried orders to the reserve brigade and participated with it in the charge which repulsed the enemy.