William Kingsmill (died 1618) was an English landowner.
He was a son of William Kingsmill (died 1592) and Bridget Raleigh (died 1607), a daughter of George Raleigh.
His home was at Sydmonton. He was Sheriff of Hampshire in 1601 and 1612.
King James and Anne of Denmark stayed at Sydmonton Court in August 1603. Anne of Denmark stayed in August 1611.
He died in January 1618.
He married Anne Wilkes or Willes, daughter of William Willes of Middleton Cheney. Their children included:
Anne, Lady Kingsmill wrote to the Earl of Salisbury on 14 June 1608, thanking him for favours shown to herself and her son.