Nicholas Upton (1400?–1457), was an English cleric, precentor of Salisbury, and writer on heraldry and the art of war.
He is thought to have been the second son of John Upton of Portlinch, Devon, by his wife Elizabeth, daughter of John Barley of Chencombe in the same county. Nicholas entered as scholar of Winchester College in 1408 under the name ‘Helyer alias Upton, Nicholas,’ and was elected Fellow of New College, Oxford, in 1415, graduating bachelor of civil law. He was ordained subdeacon on 8 March 1421; but he entered the service of Thomas de Montacute, 4th Earl of Salisbury, and fought against the French in Normandy. He also served under William de la Pole, Earl of Suffolk, and John Talbot, later Earl of Shrewsbury. He was with Salisbury at the Siege of Orléans in October–November 1428, when it was relieved by Joan of Arc and Salisbury was killed. Upton was appointed one of the executors of his will.
Soon afterwards Humphrey, Duke of Gloucester persuaded him to continue his clerical career. On 6 April 1431 he was admitted to the prebend of Dyme in Wells Cathedral, and before 2 October 1434 was rector of Chedsey, which he exchanged on that date for the rectory of Stapylford; he was also rector of Farleigh[disambiguation needed]. In 1438 he graduated bachelor of canon law from Broadgates Hall, Oxford, and on 11 April 1443 was collated to the prebend of Wildland in St Paul's Cathedral. He resigned his prebend on his election on 14 May 1446 as precentor of Salisbury Cathedral.
In 1452 he went on a mission to Rome to obtain the canonisation of Osmund], the founder of Salisbury. He reached Rome on 27 June, returning in May 1453 without accomplishing his object. He died in 1457 before 15 July, and was buried in Salisbury Cathedral.
Upton was the author of Libellus de Officio Militari; it was dedicated to Humphrey, Duke of Gloucester, and was therefore written before 1446. It consists of four parts:
- ‘De Coloribus in Armis et eorum Nobilitate ac Differentia;’
- ‘De Regulis et de Signis;’
- ‘De Animalibus et de Avibus in Armis portatis;’
- ‘De Militia et eorum [sic] Nobilitate.’ 
The book circulated in manuscript for two centuries. Parts were incorporated in the Book of St. Albans; it was transcribed by Robert Glover and was largely used by Francis Thynne. It was edited by Sir Edward Bysshe from Sir Robert Cotton's manuscript, and another belonging to Matthew Hale[disambiguation needed], both procured for Bysshe by John Selden; it was entitled Nicholai Vptoni de Studio Militari (London, 1654).
- "Upton, Nicholas". Dictionary of National Biography. London: Smith, Elder & Co. 1885–1900.
- J. P. Cooper, Ideas of Gentility in Early Modern-England, Ch. 3 (pp. 43–77) in Land, Men and Beliefs: Studies in Early-Modern History (1983), edited by G. E. Aylmer and J. S. Morrill
- A fifteenth-century manuscript of the work, possibly the original, is Addit. MS. 30946 in the British Museum; a fifteenth-century copy is in Cottonian MS. Nero C. iii.; and later copies are in Harleian MSS. 3504 and 6106, and in Trinity College, Oxford, MS. xxxvi.; extracts from it are contained in Stowe MS. 1047, f. 252, and in Rawlinson MSS. (Bodleian Library) B. 20 and B. 107.
- Cooper, p. 48
- Cooper, p. 46