Shakespearean Sonnet Structure and Rhyme Scheme

A sonnet is a fixed 14-line form that has taken different shapes depending on the language and the poet handling it. Petrarchan sonnet rhyme scheme covers the form’s general blueprint; this Recap zooms in on the variant William Shakespeare pushed to its peak in England, a variant with a rhyme scheme all its own, distinct from the one Petrarch had shaped in Italy.

The Shakespearean sonnet form runs on three quatrains and a closing couplet, 14 lines total, in iambic pentameter. The rhyme scheme is ABAB CDCD EFEF GG: each quatrain alternates two rhymes, and then the couplet closes on a rhyming pair, GG, that stands out against everything before it. It builds in stages — three blocks stacked one after another, each with its own rhyme pair, before the couplet lands the final blow.

That closing couplet does more than tie off the meter. Per the Academy of American Poets’ glossary, those two lines are where the poet often reaches a conclusion, an amplification, or even a reversal of what the three quatrains just argued — this is where the sonnet’s turn concentrates.

The sonnet Petrarch and the Canzoniere made famous works differently: an octave with crossed rhymes, ABBA ABBA, followed by a sestet that tradition closes either CDECDE or CDCDCD. Petrarch himself, per Treccani, mixed in variants like ABAB BABA or ABAB BAAB within the octave, favoring the CDE CDE pattern in the sestet; the ABBA ABBA scheme commonly treated as “the” Petrarchan form only settled into place toward the end of the 13th century, not the shape the Italian tradition started with. The turning point moves too: the Italian sonnet’s turn falls between lines eight and nine, between octave and sestet, while the Shakespearean sonnet pushes it further out, into the closing couplet.

Shakespeare didn’t invent the shift from the Italian form to the English one. Thomas Wyatt brought the Petrarchan sonnet to England in the early 16th century; according to Treccani, Wyatt is the one who turned the Italian sestet’s two tercets into a quatrain plus a couplet, the first step toward the structure that came to be called Shakespearean. Henry Howard, Earl of Surrey, then reworked the Petrarchan form further, locking in the sequence of three quatrains and a couplet rhymed ABAB CDCD EFEF GG — a structure that carries Shakespeare’s name not because he invented it, but because his 154 sonnets, published in 1609 with a cryptic dedication most likely written by the publisher, Thomas Thorpe, made it famous.

Three of those sonnets remain among the most read and, between them, show exactly how the closing couplet does its work. Sonnet 18 overturns the promise of the sonnets before it, which had urged the young man it addresses to marry and have children so his beauty would live on; here, it’s the poem itself that guarantees that immortality, and the couplet states it flatly. Sonnet 116 uses its couplet to seal an absolute definition of true love, described as unalterable and eternal, a fixed point that doesn’t bend to storms or bow to time. Sonnet 130 works differently: it strips away, one by one, the stock images of Elizabethan love poetry — eyes like the sun, lips like coral — only to flip the whole thing in the couplet, calling the poet’s love rare precisely because it skips those false comparisons.

Worked example: in the couplet of Sonnet 18, the poet writes that so long as people can breathe or eyes can see, his lines will live on and keep their subject alive — the GG rhyme closes the argument with a flat statement, after three quatrains of build-up.

The 154 sonnets aren’t a loose pile of separate poems. Per the Folger Shakespeare Library, the collection opens with 17 sonnets urging a young man to marry, moves through a long stretch — up to sonnet 126 — that declares the poet’s love for that same young man, and closes with 28 sonnets to or about a woman cast as dark and unfaithful. The rhyme scheme stays the same across all 154 sonnets, no matter the theme or the addressee.