Allen Richard Toussaint (/ˈtuːsɑːnt/; January 14, 1938 – November 10, 2015) was an American musician, songwriter, arranger, and record producer. He was an influential figure in New Orleans rhythm and blues from the 1950s to the end of the century, described as "one of popular music's great backroom figures." Many musicians recorded Toussaint's compositions. He was a producer for hundreds of recordings: the best known are "Right Place, Wrong Time", by longtime friend Dr. John, and "Lady Marmalade" by Labelle.

The youngest of three children, Toussaint was born in 1938 in New Orleans and grew up in a shotgun house in the Gert Town neighborhood, where his mother, Naomi Neville (whose name he later adopted pseudonymously for some of his works), welcomed and fed all manner of musicians as they practiced and recorded with her son. His father, Clarence, worked on the railway and played trumpet. Allen Toussaint learned piano as a child and took informal music lessons from an elderly neighbor, Ernest Pinn. In his teens he played in a band, the Flamingos, with the guitarist Snooks Eaglin, before dropping out of school. A significant early influence on Toussaint was the syncopated "second-line" piano style of Professor Longhair. Toussaint was raised Catholic.

After a lucky break at age 17, in which he stood in for Huey "Piano" Smith at a performance with Earl King's band in Prichard, Alabama, Toussaint was introduced to a group of local musicians led by Dave Bartholomew, who performed regularly at the Dew Drop Inn, a nightclub on Lasalle Street in Uptown New Orleans. His first recording was in 1957 as a stand-in for Fats Domino on Domino's record "I Want You to Know", on which Toussaint played piano and Domino overdubbed his vocals. His first success as a producer came in 1957 with Lee Allen's "Walking with Mr. Lee". He began performing regularly in Bartholomew's band, and he recorded with Fats Domino, Smiley Lewis, Lee Allen and other leading New Orleans performers.

After being spotted as a sideman by the A&R man Danny Kessler, he initially recorded for RCA Records as Al Tousan. In early 1958 he recorded an album of instrumentals, The Wild Sound of New Orleans, with a band including Alvin "Red" Tyler (baritone sax), either Nat Perrilliat or Lee Allen (tenor sax), either Justin Adams or Roy Montrell (guitar), Frank Fields (bass), and Charles "Hungry" Williams (drums). The recordings included Toussaint and Tyler's composition "Java", which first charted for Floyd Cramer in 1962 and became a number 4 pop hit for Al Hirt (also on RCA) in 1964. Toussaint recorded and co-wrote songs with Allen Orange in the early 1960s.

In 1960, Joe Banashak, of Minit Records and later Instant Records, hired Toussaint as an A&R man and record producer. He did freelance work for other labels, such as Fury. Toussaint played piano, wrote, arranged and produced a string of hits in the early and mid-1960s for New Orleans R&B artists such as Ernie K-Doe, Chris Kenner, Irma Thomas (including "It's Raining"), Art and Aaron Neville, The Showmen, and Lee Dorsey, whose first hit "Ya Ya" he produced in 1961.

The early to mid-1960s are regarded as Toussaint's most creatively successful period. Notable examples of his work are Jessie Hill's "Ooh Poo Pah Doo" (written by Hill and arranged and produced by Toussaint), Ernie K-Doe's "Mother-in-Law", and Chris Kenner's "I Like It Like That". A two-sided 1962 hit by Benny Spellman comprised "Lipstick Traces (on a Cigarette)" (covered by The O'Jays, Ringo Starr, and Alex Chilton) and the simple but effective "Fortune Teller" (covered by various 1960s rock groups, including The Rolling Stones, The Nashville Teens, The Who, The Hollies, The Throb, and The Searchers founder Tony Jackson). "Ruler of My Heart", written under his pseudonym Naomi Neville, first recorded by Irma Thomas for the Minit label in 1963, was adapted by Otis Redding under the title "Pain in My Heart" later that year, prompting Toussaint to file a lawsuit against Redding and his record company, Stax (the claim was settled out of court, with Stax agreeing to credit Naomi Neville as the songwriter). Redding's version of the song was also recorded by The Rolling Stones on their second album and was in the Grateful Dead's early repertoire. In 1964, "A Certain Girl" (originally by Ernie K-Doe) was the B-side of the first single release by The Yardbirds. The song was released again in 1980 by Warren Zevon, as the single from the album Bad Luck Streak in Dancing School; it reached 57 on Billboard's Hot 100. Mary Weiss, former lead singer of The Shangri-Las, released it as "A Certain Guy" in 2007. Linda Ronstadt released a jazzy version of "Ruler of my Heart" in 1998 on We Ran.

Toussaint credited about twenty songs to his parents, Clarence and Naomi, sometimes using the pseudonym "Naomi Neville". These include "Fortune Teller", first recorded by Benny Spellman in 1961, "Pain In My Heart," first a hit for Otis Redding in 1963, and "Work, Work, Work", recorded by The Artwoods in 1966. Alison Krauss and Robert Plant covered "Fortune Teller" on their 2007 album Raising Sand.

Toussaint was drafted into the United States Army in 1963 but continued to record when on leave. After his discharge in 1965, he joined forces with Marshall Sehorn to form Sansu Enterprises, which included a record label, Sansu, variously known as Tou-Sea, Deesu, or Kansu, and recorded Lee Dorsey, Chris Kenner, Betty Harris, and others. Dorsey had hits with several of Toussaint's songs, including "Ride Your Pony" (1965), "Working in the Coal Mine" (1966), and "Holy Cow" (1966). The core players of the rhythm section used on many of the Sansu recordings from the mid- to late 1960s, Art Neville and the Sounds, consisted of Art Neville on keyboards, Leo Nocentelli on guitar, George Porter Jr on bass, and Zigaboo Modeliste on drums. They later became known as The Meters. Their backing can be heard in songs such as Dorsey's "Ride Your Pony" and "Working in the Coal Mine", sometimes augmented by horns, which were usually arranged by Toussaint. The Toussaint-produced records of these years backed by the members of the Meters, with their increasing use of syncopation and electric instrumentation, built on the influences of Professor Longhair and others before them, but updated these strands, effectively paving the way for the development of a modern New Orleans funk sound.