John Nickolls (1710?–1745) was an English collector and antiquary.
The son of John Nickolls, a Quaker miller of Ware, Hertfordshire, he was born there in 1710 or 1711. He was apprenticed to Joseph Wyeth, merchant in London, and, after serving his time, became a partner with his father. Nickolls was elected a fellow of the Society of Antiquaries on 17 January 1740 and elected a Fellow of the Royal Society in 1744. He died of fever on 11 January 1745, and was buried at the Quaker Burying Ground, Bunhill Fields, five days later.
At his house in Trinity parish, Queenhithe, he formed an excellent library. He also collected from the bookstalls about Moorfields two thousand prints of heads; these later furnished Joseph Ames with material for his Catalogue of English Heads, London, 1748. From Wyeth's widow Nickolls received a number of letters at one time in John Milton's possession; they had since belonged to Milton's secretary, Thomas Ellwood, and had been used by Wyeth in the preparation for publication of Ellwood's Journal, which was issued in 1713. William Oldys visited Nickolls at Queenhithe on 22 December 1737, to see this collection of original letters. These documents were issued by Nickolls in 1743. His father presented on 18 Jan. 1746 the original manuscripts of the collection to the Society of Antiquaries. Oldys says in his 'Diary' that Nickolls allowed Thomas Birch to use some of them in his life of Oliver Cromwell in the General Dictionary, Historical and Critical, 1731–41. Nickolls's prints and rare pamphlets were purchased by John Fothergill.
- "Library and Archive catalog". Royal Society. Retrieved 2012-03-05.
- Among them were letters from Sir Harry Vane, Colonels Overton, Harrison, and Venables, John Bradshaw, Andrew Marvell, and others, with numerous addresses from Nonconformist ministers in Norfolk, Suffolk, Bedfordshire, Herefordshire, Kent, Dublin, and elsewhere.
- 'Original Letters and Papers of State, addressed to Oliver Cromwell, concerning the Affairs of Great Britain. From the Year mdcxlix to mdclviii, found among the Political Collections of Mr. John Milton. Now first published from the Originals.'