John Haslet (c. 1727 – January 3, 1777) was an American Presbyterian clergyman and soldier from Milford, in Kent County, Delaware.
He was a veteran of the French and Indian War and an officer of the Continental Army in the American Revolution, serving as the first Colonel of the 1st Delaware Regiment.
As the eldest son, he attended the University of Glasgow in Scotland, earned his degree in divinity in 1749 and was ordained a Presbyterian minister at Ballykelly, County Londonderry, in 1752.
In response to the request of the Continental Congress, the Lower Counties Assembly raised the 1st Delaware Regiment, placing Haslet at its command on January 19, 1776, with the rank of colonel.
Raised in early 1776, they went from north in July and August 1776, arriving in time to engage in the entire sequence of events surrounding the British capture of New York in 1776.
They fought under the command of Brigadier General William Alexander, Lord Stirling, and were responsible for holding the Gowanus Road, the far right of the Continental Army line.
At White Plains on October 28, 1776, the Delaware Regiment again fought with Colonel William Smallwood's Marylanders, reinforcing militia placed on the strategic Chatterton's Hill.
With expiring enlistments leaving fewer than 100 men remaining in his regiment, Haslet crossed the Delaware with Washington and joined the attack at the Battle of Trenton on the morning of December 26, 1776.