Canon William Greenwell, FRS, FSA, FSA Scot (23 March 1820 – 27 January 1918) was an English archaeologist and Church of England priest.
William Greenwell was born 23 March 1820 at the estate known as Greenwell Ford near Lanchester, County Durham, England. He was the eldest son of William Thomas Greenwell (1777–1856) and Dorothy Smales. He had three brothers Francis, Alan, and Henry Nicholas Greenwell, and a sister Dorothy (1821–1882) who published poetry under the name Dora Greenwell. Greenwell died 27 January 1918.
After an early education by Rev George Newby, he attended Durham School. One of his schoolmates was Henry Baker Tristram. He matriculated at University College, Durham in October 1836 and graduated Bachelor of Arts (BA) in June 1839. He started training to be a barrister at Middle Temple, but did not like London and returned to Durham in 1841 to study theology. He received a Master of Arts in 1843. Greenwell was ordained a deacon by Bishop Edward Maltby 30 June 1844 and priest 28 June 1846. He was bursar of University College in Durham from 1844 to 1847.
His family estate included the site of the ancient Roman fort Longovicium. As a child he and his brother Frank would scoop out soil covering the camp, leading to his interest in archaeology. He was a founding member of the Tyneside Naturalists' Field Club in 1846, and later that year toured Germany and Italy. In 1852 he became principal of Neville Hall in Newcastle upon Tyne. In August 1852 he presented a paper at an Archaeological Institute there. In March 1864 he excavated fourteen barrows at Danes Graves a site of the Arras Culture of the British Iron Age and was subsequently criticised by William Harrison-Broadley for his poor excavation technique. Greenwell undertook a large-scale excavation of 53 barrows at Danes Graves with John Robert Mortimer between 1897–98. Greenwell is also noted for his work on the Grimes Graves along with his treatises on electrum coinage of Cyzicus, and cataloguig of the Late Bronze Age finds from Heathery Burn Cave. Greenwell's enormous collection of antiquities, many of which date from the Neolithic or Bronze Age period in Britain, is now in the British Museum. One of his students was Augustus Pitt Rivers.