William Bedloe (20 April 1650 – 20 August 1680) was an English fraudster and informer.
He was born at Chepstow in Monmouthshire, the cousin of William Kemys (or Kemish), who became High Sheriff of Monmouthshire in 1678. He appears to have been well educated; he was certainly clever, and after moving to London in 1670 he became acquainted with some Jesuits and was occasionally employed by them. Calling himself now Captain Williams, now Lord Gerard or Lord Newport or Lord Cornwallis, he travelled from one part of Europe to another, usually accompanied by his brother James. In the 1670s he was gaoled for fraud and became an expert in all kinds of duplicity. Kenyon described him as "a habitué of a London underworld of crime and vice of which we know almost nothing".
Then in 1678, following the lead of Titus Oates, he gave an account of a supposed Popish Plot to the English government, and his version of the details of the murder of Sir Edmund Berry Godfrey was rewarded with £500. Kenyon concluded that while Bedloe probably had no direct knowledge about Godfrey's murder, he learned enough about it from his extensive contacts in the criminal underworld to tell a convincing story. His record as a confidence trickster was so notorious that he chose to dwell on it, explaining that it was his career as a criminal which enabled him to denounce the plotters. While some Government officials, like Henry Coventry, were wary of relying on such a notorious criminal, the general view was that he was too valuable as a corroborating witness to Oates to be disregarded. In the event his testimony was usually of little value, apart from the trial of Berry, Green and Hill for Godfrey's murder, of which he may have had some personal knowledge. At other Plot trials like that of Edward Colman his evidence was so weak that the Court largely disregarded it.
Emboldened by his success he denounced various Roman Catholics, married an Irish lady, and having become very popular lived in luxurious fashion. Afterwards his fortunes waned, and he died at Bristol on 20 August 1680. His dying depositions, which were taken by Sir Francis North, Chief Justice of the Common Pleas, revealed nothing of importance. Bedloe wrote a Narrative and impartial discovery of the horrid Popish Plot (1679), but all his statements are extremely untrustworthy. 
Lady Worcester, whose husband was the target of some of Bedloe's accusations called him " a man whose whole life has been a pageant of villainy and whose word would not have been taken at sixpence". At Oates's trial for perjury, Lord Chief Justice Jeffreys, who had happily condemned innocent men on Bedloe's accusations, called him "infamous Bedloe".
- Jeremy Knight, Civil War & Restoration in Monmouthshire, 2005, Logaston Press, ISBN 1-904396-41-0, p.161
- Alan Marshall, 'Bedloe, William (1650–1680)', Oxford Dictionary of National Biography, Oxford University Press, Sept 2004
- Chisholm 1911.
- Kenyon Popish Plot p.308
- Kenyon p.152
- Kenyon p.106
- Kenyon p.134
- Kenyon p.292
- Pollock, John. The Popish Plot, 1903.
- Kenyon, J.P. The Popish Plot Phoenix Press Reissues 2000
- This article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Bedloe, William". Encyclopædia Britannica 3 (11th ed.). Cambridge University Press.
- Ebsworth, Joseph Woodfall (1885). "Bedloe, William". In Stephen, Leslie. Dictionary of National Biography 4. London: Smith, Elder & Co.