Hercule Poirot (UK: /ˈɛərkjuːl ˈpwɑːroʊ/, US: /hɜːrˈkjuːl pwɑːˈroʊ/) is a fictional Belgian detective created by British writer Agatha Christie. Poirot is one of Christie's most famous and long-running characters, appearing in 33 novels, two plays (Black Coffee and Alibi), and 51 short stories published between 1920 and 1975.

Poirot has been portrayed on radio, in film and on television by various actors, including Austin Trevor, John Moffatt, Albert Finney, Peter Ustinov, Ian Holm, Tony Randall, Alfred Molina, Orson Welles, David Suchet, Kenneth Branagh, and John Malkovich.

Poirot's name was derived from two other fictional detectives of the time: Marie Belloc Lowndes's Hercule Popeau and Frank Howel Evans's Monsieur Poiret, a retired French police officer living in London. Evans's Jules Poiret "was small and rather heavyset, hardly more than five feet, but moved with his head held high. The most remarkable features of his head were the stiff military moustache. His apparel was neat to perfection, a little quaint and frankly dandified." He was accompanied by Captain Harry Haven, who had returned to London from a Colombian business venture ended by a civil war. 

A more obvious influence on the early Poirot stories is that of Arthur Conan Doyle. In An Autobiography, Christie states, "I was still writing in the Sherlock Holmes tradition – eccentric detective, stooge as.sistant, with a Lestrade-type Scotland Yard detective, Inspector Japp". Conan Doyle acknowledged basing his detective stories on the model of Edgar Allan Poe's C. Auguste Dupin and his anonymous narrator, and basing his character Sherlock Holmes on Joseph Bell, who in his use of "ratiocination" prefigured Poirot's reliance on his "little grey cells". Poirot also bears a striking resemblance to A. E. W. Mason's fictional detective Inspector Hanaud of the French Sûreté, who first appeared in the 1910 novel At the Villa Rose and predates the first Poirot novel by 10 years.

Christie's Poirot was clearly the result of her early development of the detective in her first book, written in 1916 and published in 1920. The large number of refugees in the country who had fled the German invasion of Belgium in August to November 1914 served as a plausible explanation of why such a skilled detective would be available to solve mysteries at an English country house. At the time of Christie's writing, it was considered patriotic to express sympathy towards the Belgians, since the invasion of their country had constituted Britain's casus belli for entering World War I, and British wartime propaganda emphasised the "Ra.pe of Belgium".

A statuette of Poirot in Ellezelles, Belgium