Development of the album began on November 2, 2001 and was released just under two years later in 2003. At the time of development, only will.i.am, apl.de.ap and Taboo were to feature on the album. During the production of "Shut Up" (the second single released from the album), they realized that a female vocal would work well with the song. Originally, Nicole Scherzinger (lead singer of the Pussycat Dolls) was approached to make a guest appearance on the record. She was forced to decline because she already was signed to a contract with Eden's Crush. Danté Santiago then introduced Fergie to Will who was impressed with her vocal talents. She immediately formed a bond with the band and became a permanent member of the Peas and her photo was printed onto the album cover. Nine out of the fourteen tracks were composed by lyricist Robbie Fisher, who has been working closely with the band since the beginning stages of the album.
John Bush from Allmusic said that Elephunk "possesses some of the most boundary-pushing productions in contemporary, (mostly) uncommercial hip-hop" and gave the album a 4/5 star rating. Chris Nettleton from Drowned in Sound complimented the album saying: "This record is full of first rate rapping, first rate tunes, first rate instrumentation. Look on the surface, and you've got an album full of memorable songs, hooks that lodge in your mind... but look in depth, and it's quality from the top down." In his consumer guide for The Village Voice, Robert Christgau commented that the group "remain unbelievable, but in pop that's just one more aesthetic nuance", and stated, "In which the unbelievably dull El Lay alt-rappers fabricate the brightest actual pop album of 2003."Entertainment Weekly had more of a negative view on the record: "They try dancehall ('Hey Mama'), salsa ('Latin Girls'), even nu-metal ('Anxiety' with Papa Roach), but the biggest offense for a once smart-sounding rap collective is 'Where Is the Love?', the horrifyingly trite single. It's enough to make longtime fans wonder, 'Where are the Peas?'" The album received a C grade. At Metacritic, which assigns a normalized rating out of 100 to reviews from mainstream critics, the album has received an average score of 66, based on 15 reviews indicating generally positive reviews.
In the United States, Elephunk reached number 14 on the Billboard Top 200 and is their first album to chart in the top 15. It gained even more commercial success in the UK Album Charts where it reached number 3. It has sold over 1.6 million copies in the UK and 8.5 million copies worldwide. The singles "Where Is The Love?" and "Shut Up" reached number 1. "Hey Mama" has been used for several advertisements including advertisements for Apple and iTunes. "Let's Get It Started" also received universal acclaim in the media section where a cover version of the song appears in the film Hot Tub Time Machine. After the success of Elephunk, the Peas were approached by EA games to feature some of their music on the 2004 game The Urbz. They remixed some of the tracks on Elephunk and translated it into Simlish and created new tracks for the game. They also feature in the game as playable characters.