Henry Danvers, 1st Earl of Danby, KG (28 June 1573 – 20 January 1643) was an English soldier. Outlawed after a killing, he regained favour and became a Knight of the Garter.
He was the second son of Sir John Danvers, Knt., of Dauntsey, Wiltshire, by his wife Elizabeth Nevill, the youngest daughter and coheiress of John Nevill, 4th Baron Latymer. He was born at Dauntsey on 28 June 1573, and at an early age became a page to Sir Philip Sidney, whom he accompanied to the Low Countries, and was probably present at the battle of Zutphen in 1586. After his master's death he served as a volunteer under Maurice, Count of Nassau, who appointed him at the age of eighteen to the command of a company of infantry. Danvers took part in the siege of Rouen in 1591, and was there knighted for his services in the field by Robert Devereux, 2nd Earl of Essex, in command of the expedition.
His father died on 19 December 1593, and on 4 October 1594 Henry Long, son of Robert Long, and brother of Sir Walter Long was killed. A feud had existed between the Long and Danvers families for some time past. According to one account, Henry Long was dining in the middle of the day with a party of friends in Corsham, when Danvers, followed by his brother Charles and a number of retainers, burst into the room, and shot Long dead on the spot. The brothers then fled on horseback to Whitley Lodge, near Titchfield, the seat of Henry Wriothesley, 3rd Earl of Southampton. With Southampton's assistance they succeeded after some days in making their way out of the country. A coroner's inquisition was held, and the brothers were outlawed. Another version of the story asserted that Henry Long was killed by Sir Henry Danvers in defending his brother Sir Charles against Long and his company.