A quatorzain (from French quatorze, fourteen) is an anamorphic or abortive poem or sonnet. It consists of 14 lines and is, like a sonnet, divided into two tercets and two quatrains.

The term is used in English literature, as opposed to sonnet, for a poem in fourteen rhymed iambic lines closing (as a sonnet strictly never does) with a couplet. The distinction was long neglected because the English poets of the 16th century had failed to apprehend the true form of the sonnet, and called Petrarch's and other Italian poets' sonnets quatorzains, and their own incorrect quatorzains sonnets. Almost all the so-called sonnets of the Elizabethan cycles, including those of William Shakespeare, Philip Sidney, Edmund Spenser and Samuel Daniel, are really quatorzains. They consist of three quatrains of alternate rhyme, not repeated in the successive quatlains, and the whole closes with a couplet. An example of the form can be found in the following, published by Michael Drayton in 1602:

Dear, why should you commend me to my rest,

When now the night doth summon all to sleep?

Methinks this time becometh lovers best,

Night was ordained together friends to keep.

How happy are all other living things

Which though the day conjoin by several flight,

The quiet evening yet together brings,

And each returns unto his love at night,

O thou that art so courteous unto all,

Why shouldst thou, Night, abuse me only thus,

That every creature to his kind dust call,

And yet tis thou dost only sever us?

Well could I wifh it would be ever day,

If, when night comes, you bid me go away.

John Donne, and afterwards John Milton, fought against the facility and incorrectness of this form of metre and adopted the Italian form of sonnet. During the 19th century, most poets of distinction prided themselves on following the strict Petrarchan model of the sonnet, and particularly in avoiding the final couplet. In his most mature period, however, John Keats returned to the quatorzain, perhaps in emulation with Shakespeare.

Additional examples of this form include Keats' When I have fears, Standing aloof in giant ignorance, Bright Star, and S. T. Coleridge's The Fancy in Nubibus (1819).