Grub Street is a literary term used to describe an underworld of literary penury and its products. Now renamed Milton Street, Grub Street was a street in London off Chiswell Street by Finsbury Square, which was occupied in the 18th century by impoverished writers reduced to turning to third-rate poems, reference books and histories to make a living. Grub Street writers are known as hacks: an abbreviation of hackney, which means a hired horse.

The term is covered as such in George Gissing's Victorian novel New Grub Street (1891), a story of men and women forced to make their living by writing. In 1726, Jonathan Swift (1667-1745) wrote his poem Advice to the Grub Street verse-writers addressing them as follows:

Ye poets ragged and forlorn
Down from your garrets haste
Ye rhymers, dead as soon as born
Not yet consign'd to paste