The Baconian theory of Shakespeare authorship holds that Sir Francis Bacon, philosopher, essayist and scientist, wrote the plays which were publicly attributed to William Shakespeare. Various explanations are offered for this alleged subterfuge, most commonly that Bacon's rise to high office might have been hindered were it to become known that he wrote plays for the public stage. Thus the plays were credited to Shakespeare, who was merely a front to shield the identity of Bacon.

The question of the true authorship of Shakespeare's plays began when the play Richard II was performed in 1600 with some scenes included that were not in the printed 1598 edition (those scenes were included in the 1608 edition). Robert Cecil, the Lord Privy Seal for Queen Elizabeth, and Elizabeth herself, adjudged those scenes to be seditious and allegedly set out to discover the true identity of the play's author. Ben Jonson and Christopher Marlowe were suspected. There is a story, probably apocryphal, that William Shakespeare was spirited out of England to Scotland or perhaps Germany to avoid prosecution for the sedition that Cecil saw in Richard II and Henry IV, Part 1. Cecil and Elizabeth also objected to John Hayward's The First Part of the Life and Raigne of King Henrie IIII – which he dedicated to the Earl of Essex, who was later executed for treason.

Though Cecil supposedly gave Bacon the task of finding the true author, Bacon himself was later the first serious alternative candidate suggested as the author of Shakespeare's plays. The theory was first put forth in the mid-nineteenth century, based on perceived correspondences between the philosophical ideas found in Bacon’s writings and the works of Shakespeare. Later, proponents claimed to have found legal and autobiographical allusions and cryptographic ciphers and codes in the plays and poems to buttress the theory. All but a few academic Shakespeare scholars reject the arguments for Baconian authorship, as well as those for all other alternative authors.

The Baconian theory gained great popularity and attention in the late nineteenth and early twentieth centuries, although since the mid-twentieth century the primacy of his candidacy as author of the Shakespeare canon has been supplanted by that of Edward de Vere, 17th Earl of Oxford. Despite the academic consensus that Shakespeare wrote the works bearing his name and the decline of the theory, supporters of Bacon continue to argue for his candidacy through organizations, books, newsletters, and websites.