Cecily of York (20 March 1469 – 24 August 1507), also known as Cecelia, was the third daughter of King Edward IV of England and his queen consort Elizabeth Woodville.

Shortly after the death of her father and the usurpation of the throne by her uncle King Richard III, Cecily and her siblings were declared illegitimate. Queen Elizabeth, fearing for the children's lives, moved them to Westminster Abbey, where the late king's family received asylum and spent about a year. After Richard III promised not to harm the children, Cecily and her sisters went to court. Soon there were rumours that the king was going to marry one of his nieces – Elizabeth or Cecily. However, shortly before his death, Richard III arranged the marriage of Cecily to one of his supporters – Ralph Scrope, the younger brother of the 6th Baron Scrope of Masham, who was much lower in status by birth than the princess.

When Richard III died at the Battle of Bosworth and the throne was taken by Henry Tudor, the act recognising the children of Edward IV as bastards was repealed, and Cecily's marriage was annulled as not being in the interests of the dynasty. In 1488, Cecily married John Welles, 1st Viscount Welles, a relative of the king's mother Lady Margaret Beaufort; in this second marriage, Cecily gave birth to two daughters.

In 1499, she became a widow. After several years of mourning, and without the permission of the king, Cecily married a Lincolnshire squire, Sir Thomas Kyme, with whom she gave birth to two more children. Cecily's marriage to Kyme and their children were not recognised by the Crown, and she herself was banished from court and deprived of the possessions inherited from her second husband's will. Nevertheless, the princess maintained a good relationship with the king's mother: it was Lady Margaret Beaufort who paid part of the expenses of Cecily's funeral in 1507.