Dudley Carleton, 1st Viscount Dorchester (10 March 1573 – 15 February 1632) was an English art collector, diplomat and Secretary of State.
He was the second son of Anthony Carleton of Brightwell Baldwin, Oxfordshire, and of Joyce Goodwin, daughter of John Goodwin of Winchendon, Buckinghamshire. He was born on 10 March 1573, and educated at Westminster School and Christ Church, Oxford, where he graduated B.A, in 1595, M.A. in 1600. After graduating he took employment with Sir Edward Norreys at Ostend, as secretary. In 1598 he attended Francis Norreys, nephew of Sir Edward, on a diplomatic mission to Paris led by Charles Howard, 1st Earl of Nottingham. In 1603 he became secretary to Thomas Parry, ambassador in Paris, but left the position shortly, for one in the household of Henry Percy, 9th Earl of Northumberland.
Carleton was returned to the parliament of 1604 as member for St Mawes. As a parliamentarian, Carleton was an apologist for the court line in unpopular causes, as in the debate over the "Apology" of 1604.
Through his connection with the Earl of Northumberland, his name was associated with the Gunpowder Plot in 1605. Carleton was out of the country in November 1605; Francis Norreys (by now Earl of Berkshire) had gone to Spain earlier in the year with the Earl of Nottingham who was Ambassador in Madrid; and Carleton had accompanied him. Norreys fell ill in Paris on the journey home, and Carleton was in Paris when it was discovered that the plotters' house, adjacent to the vault that had contained the gunpowder under Parliament, had been sublet, by Thomas Percy in May 1604, by using the names of Carleton and another member of the Northumberland household. Summoned to return, Carleton was detained for a month, but was released through the influence of Robert Cecil, 1st Earl of Salisbury. Cecil in fact knew well enough that Carleton had been held up in Paris from September, from letters detailing the treatment of Norreys who was a political ally.