William Shakespeare (baptised 26 April 1564; died 23 April 1616) was an English poet and playwright, widely regarded as the greatest writer in the English language and the world's pre-eminent dramatist. He is often called England's national poet and the "Bard of Avon". His surviving works, including some collaborations, consist of about 38 plays, 154 sonnets, two long narrative poems, and several other poems. His plays have been translated into every major living language and are performed more often than those of any other playwright.

Shakespeare was born and raised in Stratford-upon-Avon. At the age of 18, he married Anne Hathaway, with whom he had three children: Susanna, and twins Hamnet and Judith. Between 1585 and 1592, he began a successful career in London as an actor, writer, and part owner of a playing company called the Lord Chamberlain's Men, later known as the King's Men. He appears to have retired to Stratford around 1613, where he died three years later. Few records of Shakespeare's private life survive, and there has been considerable speculation about such matters as his physical appearance, sexuality, religious beliefs, and whether the works attributed to him were written by others. Shakespeare produced most of his known work between 1589 and 1613. His early plays were mainly comedies and histories, genres he raised to the peak of sophistication and artistry by the end of the sixteenth century. He then wrote mainly tragedies until about 1608, including Hamlet, King Lear, and Macbeth, considered some of the finest works in the English language. In his last phase, he wrote tragicomedies, also known as romances, and collaborated with other playwrights. Many of his plays were published in editions of varying quality and accuracy during his lifetime. In 1623, two of his former theatrical colleagues published the First Folio, a collected edition of his dramatic works that included all but two of the plays now recognised as Shakespeare's. Shakespeare was a respected poet and playwright in his own day, but his reputation did not rise to its present heights until the nineteenth century. The Romantics, in particular, acclaimed Shakespeare's genius, and the Victorians worshipped Shakespeare with a reverence that George Bernard Shaw called "bardolatry". In the twentieth century, his work was repeatedly adopted and rediscovered by new movements in scholarship and performance. His plays remain highly popular today and are constantly studied, performed and reinterpreted in diverse cultural and political contexts throughout the world.

William Shakespeare was the son of John Shakespeare, a successful glover and alderman originally from Snitterfield, and Mary Arden, the daughter of an affluent landowning farmer. He was born in Stratford-upon-Avon and baptised on 26 April 1564. His actual birthdate is unknown, but is traditionally observed on 23 April, St George's Day. This date, which can be traced back to an eighteenth-century scholar's mistake, has proved appealing because Shakespeare died on 23 April 1616. He was the third child of eight and the eldest surviving son. Although no attendance records for the period survive, most biographers agree that Shakespeare may have been educated at the King's New School in Stratford, a free school chartered in 1553, about a quarter of a mile from his home. Grammar schools varied in quality during the Elizabethan era, but the curriculum was dictated by law throughout England, and the school would have provided an intensive education in Latin grammar and the classics.

At the age of 18, Shakespeare married the 26-year-old Anne Hathaway. The consistory court of the Diocese of Worcester issued a marriage licence on 27 November 1582. Two of Hathaway's neighbours posted bonds the next day as surety that there were no impediments to the marriage. The couple may have arranged the ceremony in some haste, since the Worcester chancellor allowed the marriage banns to be read once instead of the usual three times. Anne's pregnancy could have been the reason for this. Six months after the marriage, she gave birth to a daughter, Susanna, who was baptised on 26 May 1583. Twins, son Hamnet and daughter Judith, followed almost two years later and were baptised on 2 February 1585. Hamnet died of unknown causes at the age of 11 and was buried on 11 August 1596.

After the birth of the twins, there are few historical traces of Shakespeare until he is mentioned as part of the London theatre scene in 1592. Because of this gap, scholars refer to the years between 1585 and 1592 as Shakespeare's "lost years". Biographers attempting to account for this period have reported many apocryphal stories. Nicholas Rowe, Shakespeare’s first biographer, recounted a Stratford legend that Shakespeare fled the town for London to escape prosecution for deer poaching. Another eighteenth century story has Shakespeare starting his theatrical career minding the horses of theatre patrons in London. John Aubrey reported that Shakespeare had been a country schoolmaster. Some twentieth century scholars have suggested that Shakespeare may have been employed as a schoolmaster by Alexander Hoghton of Lancashire, a Catholic landowner who named a certain "William Shakeshafte" in his will. No evidence substantiates such stories other than hearsay collected after his death and the name Shakeshafte was common in the Lancashire area.

It is not known exactly when Shakespeare began writing, but contemporary allusions and records of performances show that several of his plays were on the London stage by 1592. He was well enough known in London by then to be attacked in print by the playwright Robert Greene:

...there is an upstart Crow, beautified with our feathers, that with his Tiger's heart wrapped in a Player's hide, supposes he is as well able to bombast out a blank verse as the best of you: and being an absolute Johannes factotum, is in his own conceit the only Shake-scene in a country.

Scholars differ on the exact meaning of these words, but most agree that Greene is accusing Shakespeare of reaching above his rank in trying to match university educated writers, such as Christopher Marlowe, Thomas Nashe and Greene himself. The italicised phrase parodying the line "Oh, tiger's heart wrapped in a woman's hide" from Shakespeare’s Henry VI, part 3, along with the pun "Shake-scene", identifies Shakespeare as Greene’s target. Greene’s attack is the first recorded mention of Shakespeare’s career in the theatre. Biographers suggest that his career may have begun any time from the mid-1580s to just before Greene’s remarks. From 1594, Shakespeare's plays were performed only by the Lord Chamberlain's Men, a company owned by a group of players, including Shakespeare, that soon became the leading playing company in London. After the death of Queen Elizabeth in 1603, the company was awarded a royal patent by the new king, James I, and changed its name to the King's Men.

In 1599, a partnership of company members built their own theatre on the south bank of the Thames, which they called the Globe. In 1608, the partnership also took over the Blackfriars indoor theatre. Records of Shakespeare's property purchases and investments indicate that the company made him a wealthy man. In 1597, he bought the second-largest house in Stratford, New Place, and in 1605, he invested in a share of the parish tithes in Stratford.

Some of Shakespeare's plays were published in quarto editions from 1594. By 1598, his name had become a selling point and began to appear on the title pages. Shakespeare continued to act in his own and other plays after his success as a playwright. The 1616 edition of Ben Jonson's Works names him on the cast lists for Every Man in His Humour (1598) and Sejanus, His Fall (1603). The absence of his name from the 1605 cast list for Jonson’s Volpone is taken by some scholars as a sign that his acting career was nearing its end. The First Folio of 1623, however, lists Shakespeare as one of "the Principal Actors in all these Plays", some of which were first staged after Volpone, although we cannot know for certain which roles he played. In 1610, John Davies of Hereford wrote that "good Will" played "kingly" roles. In 1709, Rowe passed down a tradition that Shakespeare played the ghost of Hamlet's father. Later traditions maintain that he also played Adam in As You Like It and the Chorus in Henry V, though scholars doubt the sources of the information.

Shakespeare divided his time between London and Stratford during his career. In 1596, the year before he bought New Place as his family home in Stratford, Shakespeare was living in the parish of St. Helen's, Bishopsgate, north of the River Thames. He moved across the river to Southwark by 1599, the year his company constructed the Globe Theatre there. By 1604, he had moved north of the river again, to an area north of St Paul's Cathedral with many fine houses. There he rented rooms from a French Huguenot called Christopher Mountjoy, a maker of ladies' wigs and other headgear.

Rowe was the first biographer to pass down the tradition that Shakespeare retired to Stratford some years before his death; but retirement from all work was uncommon at that time, and Shakespeare continued to visit London. In 1612 he was called as a witness in a court case concerning the marriage settlement of Mountjoy's daughter, Mary. In March 1613 he bought a gatehouse in the former Blackfriars priory; and from November 1614 he was in London for several weeks with his son-in-law, John Hall.

After 1606 – 1607, Shakespeare wrote fewer plays, and none are attributed to him after 1613. His last three plays were collaborations, probably with John Fletcher, who succeeded him as the house playwright for the King’s Men.

Shakespeare died on 23 April 1616 and was survived by his wife and two daughters. Susanna had married a physician, John Hall, in 1607, and Judith had married Thomas Quiney, a vintner, two months before Shakespeare’s death.

In his will, Shakespeare left the bulk of his large estate to his elder daughter Susanna. The terms instructed that she pass it down intact to "the first son of her body". The Quineys had three children, all of whom died without marrying. The Halls had one child, Elizabeth, who married twice but died without children in 1670, ending Shakespeare’s direct line. Shakespeare's will scarcely mentions his wife, Anne, who was probably entitled to one third of his estate automatically. He did make a point, however, of leaving her "my second best bed", a bequest that has led to much speculation. Some scholars see the bequest as an insult to Anne, whereas others believe that the second-best bed would have been the matrimonial bed and therefore rich in significance.

Shakespeare was buried in the chancel of the Holy Trinity Church two days after his death. The epitaph carved into the stone slab covering his grave includes a curse against moving his bones, which was carefully avoided during restoration of the church in 2008:

Good frend for Iesvs sake forbeare,

To digg the dvst encloased heare.

Bleste be ye man yt spares thes stones,

And cvrst be he yt moves my bones.

Sometime before 1623, a funerary monument was erected in his memory on the north wall, with a half-effigy of him in the act of writing. Its plaque compares him to Nestor, Socrates, and Virgil. In 1623, in conjunction with the publication of the First Folio, the Droeshout engraving was published.

Shakespeare has been commemorated in many statues and memorials around the world, including funeral monuments in Southwark Cathedral and Poet's Corner in Westminster Abbey.

Most playwrights of the period typically collaborated with others at some point, and critics agree that Shakespeare did the same, mostly early and late in his career. Some attributions, such as Titus Andronicus and the early history plays, remain controversial, while The Two Noble Kinsmen and the lost Cardenio have well-attested contemporary documentation. Textual evidence also supports the view that several of the plays were revised by other writers after their original composition.

The first recorded works of Shakespeare are Richard III and the three parts of Henry VI, written in the early 1590s during a vogue for historical drama. Shakespeare's plays are difficult to date, however, and studies of the texts suggest that Titus Andronicus, The Comedy of Errors, The Taming of the Shrew and The Two Gentlemen of Verona may also belong to Shakespeare’s earliest period. His first histories, which draw heavily on the 1587 edition of Raphael Holinshed's Chronicles of England, Scotland, and Ireland, dramatise the destructive results of weak or corrupt rule and have been interpreted as a justification for the origins of the Tudor dynasty. The early plays were influenced by the works of other Elizabethan dramatists, especially Thomas Kyd and Christopher Marlowe, by the traditions of medieval drama, and by the plays of Seneca. The Comedy of Errors was also based on classical models, but no source for The Taming of the Shrew has been found, though it is related to a separate play of the same name and may have derived from a folk story. Like The Two Gentlemen of Verona, in which two friends appear to approve of rape, the Shrew's story of the taming of a woman's independent spirit by a man sometimes troubles modern critics and directors.

Shakespeare's early classical and Italianate comedies, containing tight double plots and precise comic sequences, give way in the mid-1590s to the romantic atmosphere of his greatest comedies. A Midsummer Night's Dream is a witty mixture of romance, fairy magic, and comic lowlife scenes. Shakespeare's next comedy, the equally romantic Merchant of Venice, contains a portrayal of the vengeful Jewish moneylender Shylock, which reflects Elizabethan views but may appear derogatory to modern audiences. The wit and wordplay of Much Ado About Nothing, the charming rural setting of As You Like It, and the lively merrymaking of Twelfth Night complete Shakespeare's sequence of great comedies. After the lyrical Richard II, written almost entirely in verse, Shakespeare introduced prose comedy into the histories of the late 1590s, Henry IV, parts 1 and 2, and Henry V. His characters become more complex and tender as he switches deftly between comic and serious scenes, prose and poetry, and achieves the narrative variety of his mature work. This period begins and ends with two tragedies: Romeo and Juliet, the famous romantic tragedy of sexually charged adolescence, love, and death; and Julius Caesar — based on Sir Thomas North's 1579 translation of Plutarch's Parallel Lives — which introduced a new kind of drama. According to Shakespearean scholar James Shapiro, in Julius Caesar "the various strands of politics, character, inwardness, contemporary events, even Shakespeare's own reflections on the act of writing, began to infuse each other".

In the early 1600s, Shakespeare wrote the so-called "problem plays" Measure for Measure, Troilus and Cressida, and All's Well That Ends Well and a number of his best known tragedies. Many critics believe that Shakespeare's greatest tragedies represent the peak of his art. The titular hero of one of Shakespeare's most famous tragedies, Hamlet, has probably been discussed more than any other Shakespearean character, especially for his famous soliloquy "To be or not to be; that is the question". Unlike the introverted Hamlet, whose fatal flaw is hesitation, the heroes of the tragedies that followed, Othello and King Lear, are undone by hasty errors of judgement. The plots of Shakespeare's tragedies often hinge on such fatal errors or flaws, which overturn order and destroy the hero and those he loves. In Othello, the villain Iago stokes Othello's sexual jealousy to the point where he murders the innocent wife who loves him. In King Lear, the old king commits the tragic error of giving up his powers, initiating the events which lead to the murder of his daughter and the torture and blinding of the Earl of Gloucester. According to the critic Frank Kermode, "the play offers neither its good characters nor its audience any relief from its cruelty". In Macbeth, the shortest and most compressed of Shakespeare's tragedies, uncontrollable ambition incites Macbeth and his wife, Lady Macbeth, to murder the rightful king and usurp the throne, until their own guilt destroys them in turn. In this play, Shakespeare adds a supernatural element to the tragic structure. His last major tragedies, Antony and Cleopatra and Coriolanus, contain some of Shakespeare's finest poetry and were considered his most successful tragedies by the poet and critic T.S. Eliot.

In his final period, Shakespeare turned to romance or tragicomedy and completed three more major plays: Cymbeline, The Winter's Tale and The Tempest, as well as the collaboration, Pericles, Prince of Tyre. Less bleak than the tragedies, these four plays are graver in tone than the comedies of the 1590s, but they end with reconciliation and the forgiveness of potentially tragic errors. Some commentators have seen this change in mood as evidence of a more serene view of life on Shakespeare's part, but it may merely reflect the theatrical fashion of the day. Shakespeare collaborated on two further surviving plays, Henry VIII and The Two Noble Kinsmen, probably with John Fletcher.