Thomas Love Peacock (18 October 1785 – 23 January 1866) was an English novelist, poet, and official of the East India Company. He was a close friend of Percy Bysshe Shelley, and they influenced each other's work. Peacock wrote satirical novels, each with the same basic setting: characters at a table discussing and criticising the philosophical opinions of the day.

Peacock was born in Weymouth, Dorset, the son of Samuel Peacock and his wife Sarah Love, daughter of Thomas Love, a retired master of a man-of-war in the Royal Navy. His father was a glass merchant in London, partner of a Mr Pellatt, presumed to be Apsley Pellatt (1763–1826). Peacock went with his mother to live with her family at Chertsey in 1791 and in 1792 went to a school run by Joseph Harris Wicks at Englefield Green where he stayed for six and a half years.

Peacock's father died in 1794 in "poor circumstances" leaving a small annuity. Peacock's first known poem was an epitaph for a school fellow written at the age of ten, and another on his Midsummer Holidays was written when he was thirteen. Around that time in 1798 he was abruptly taken from school and from then on was entirely self-educated.

In February 1800, Peacock became a clerk with Ludlow Fraser Company, who were merchants in the City of London. He lived with his mother on the firm's premises at 4 Angel Court Throgmorton Street. He won the eleventh prize from the Monthly Preceptor for a verse answer to the question "Is History or Biography the More Improving Study?". He also contributed to "The Juvenile Library", a magazine for youth whose competitions excited the emulation of several other boys including Leigh Hunt, de Quincey, and W. J. Fox. He began visiting the Reading Room of the British Museum and continued doing so for many years, diligently studying the best literature in Greek, Latin, French, and Italian. In 1804 and 1806 he published two volumes of poetry, The Monks of St. Mark and Palmyra. Some of Peacock's juvenile compositions were privately printed by Sir Henry Cole.

In around 1806 Peacock left his job in the city and during the year made a solitary walking tour of Scotland. The annuity left by his father expired in October 1806. In 1807 he returned to live at his mother's house at Chertsey. He was briefly engaged to Fanny Faulkner, but it was broken off through the interference of her relations. His friends, as he hints, thought it wrong that so clever a man should be earning so little money. In the autumn of 1808 he became private secretary to Sir Home Popham, commanding the fleet before Flushing. By the end of the year he was serving Captain Andrew King aboard HMS Venerable in the Downs. His preconceived affection for the sea did not reconcile him to nautical realities. "Writing poetry," he says, "or doing anything else that is rational, in this floating inferno, is next to a moral impossibility. I would give the world to be at home and devote the winter to the composition of a comedy." He did write prologues and addresses for dramatic performances on board HMS Venerable. His dramatic taste then and for the next nine years resulted in attempts at comedies and lighter pieces, all of which lacked ease of dialogue and suffered from over-elaborated incident and humour. He left HMS Venerable in March 1809 at Deal and walked around Ramsgate in Kent before returning home to Chertsey. He had sent his publisher Edward Hookham a little poem of the River Thames which he expanded during the year into "The Genius of the Thames". On 29 May he set out on a two-week expedition to trace the course of the Thames from its source to Chertsey and spent two or three days staying in Oxford.

Peacock travelled to North Wales in January 1810 where he visited Tremadog and settled at Maentwrog in Merionethshire. At Maentwrog he was attracted to the parson's daughter Jane Gryffydh, whom he referred to as the "Caernavonshire nymph". Early in June 1810, the Genius of the Thames was published by Thomas and Edward Hookham. Early in 1811 he left Maentwrog to walk home via South Wales. He climbed Cadair Idris and visited Edward Scott at Bodtalog near Tywyn. He also visited William Madocks at Dolmelynllyn. His journey included Aberystwyth and Devil's Bridge, Ceredigion. Later in 1811, his mother's annuity expired and she had to leave Chertsey and moved to Morven Cottage Wraysbury near Staines with the help of some friends. In 1812 they had to leave Morven Cottage over problems paying tradesmen's bills.

In 1812 Peacock published another elaborate poem, The Philosophy of Melancholy, and in the same year made the acquaintance of Shelley. He wrote in his memoir of Shelley, that he "saw Shelley for the first time just before he went to Tanyrallt", whither Shelley proceeded from London in November 1812 (Hogg's Life of Shelley, vol. 2, pp. 174, 175.) Thomas Hookham, the publisher of all Peacock's early writings, was possibly responsible for the introduction. It was Hookham's circulating library which Shelley used for many years, and Hookham had sent The Genius of the Thames to Shelley, and in the Shelley Memorials, pp. 38–40, is a letter from the poet dated 18 August 1812, extolling the poetical merits of the performance and with equal exaggeration censuring what he thought the author's misguided patriotism. Peacock and Shelley became friends and Peacock influenced Shelley's fortunes both before and after his death.

In the winter of 1813 Peacock accompanied Shelley and his first wife Harriet to Edinburgh. Peacock was fond of Harriet, and in his old age defended her reputation from slanders spread by Jane, Lady Shelley, the daughter-in-law of Shelley's second wife Mary.