"One Week" is a 1998 hit single by Barenaked Ladies, the first single off their 1998 album Stunt. It was written by Ed Robertson, who features on the lead vocal of the rapped verses. Steven Page sings lead on the song's choruses, while the two co-lead the prechoruses in harmony. The song is notable for its significant number of pop culture references. It is one of the band's signature songs.

"One Week" is the band's best best-performing single on the charts in both the United States and UK, though it slightly under-performed several other singles in the band's native Canada. It was the band's first and, as of 2009, only number one single in the U.S. on both the Hot 100 (for one week) and the U.S. Modern Rock Tracks (for five non-consecutive weeks); The band had begun breaking in the there with "The Old Apartment" and "Brian Wilson", both barely breaking the top 100 of the US chart, paving the way for "One Week" to become the band's breakout single. The band's US chart success has not been equalled, and was neared only by followup single "It's All Been Done", and "Pinch Me", the first single off followup album Maroon; Both broke the top 50 of the U.S. Hot 100.

Ed Robertson wrote the ideas for the non-rap 'choruses' with the concept being the structure of a fight where the protagonist knows they are wrong and is just trying to save face. He wanted to come up with a rapping verse for the song but all attempts failed. Bandmate Steven Page suggested he simply improvise the rap as the two commonly did onstage every night. Robertson heeded the advice and set up a video camera. He improvised the song at a slower pace to make rhyming easier and arrived at about four minutes of rap. He sent it to Page who told him not to change a word. Two minutes of the improvising was almost directly compiled (with very little, if any, tweaking) into the verses of the song. As it is improvised, it is not intended to directly have any relation to the plot of the chorus sections. The lyrics in the liner notes from Stuntcontain some additional lines that did not make it into the recorded version.

Band members have stated that the first live run-through of "One Week" did not go well, and that it took some time to get the song to sound good live. The instrumental parts are played by band members (notably Ed Robertson and Steven Page on guitar, and Kevin Hearn) sometimes on guitar and sometimes on keyboards; as well, while Hearn was away from touring shortly after the song's release, his place at shows was taken by one of two other musicians on keyboards who each added their own unique parts to the song, helping to shape its live sound early.

The song gained renewed popularity when it was featured in an ad for the Mitsubishi Lancer, with groups of young people in the car seeming to sing along until they could not keep up with the rapid-fire lyrics. It was featured on the third installment of Big Shiny Tunes.

In performances starting in 2003, the band developed an acoustic, bluegrass version of the song. It is typically used in a new performance setting they developed on the Peepshow Tour that year, in which they play acoustically while they stand around and sing into one omni-directional microphone.

With the departure of Page in early 2009, Robertson has taken over singing Page's lead chorus vocal, while Page's harmonies have been performed by drummer Tyler Stewart.

Verse 1

Verse 2

Outro

The music video was directed by McG and begins with them singing in a royal court, featuring a singing girl on a wind-up pedestal, similar to a scene from the movie Chitty Chitty Bang Bang. During the interlude they make an escape and sing while driving a lookalike of The General Lee from The Dukes of Hazzard(using the numbers 07 instead of 01 and minus the Confederate flag on the roof) and Starsky & Hutch's Ford Gran Torino. The band drives into a suburb, where they perform a concert in front of a trailer, with a female motorcyclist, dressed like Evel Knievel, performing stunts. The video ends with a shot of the cyclist stuck on a tree. The video features Carmit Bachar from the Pussycat Dolls, playing an angel.

"One Week" is in the video game "KR: American Idol Encore" as downloadable content. It is also on the game Karaoke Revolution as a playable song.

The song appeared in a 2002 commercial for the Mitsubishi Lancer.

"Weird Al" Yankovic has parodied "One Week". His version, called "Jerry Springer", features lyrics about The Jerry Springer Show. ApologetiX has also parodied this song on their Biblical Graffitialbum. Their version is called "One Way", and claims that Jesus Christ is the one way to Heaven. In January 2009, Collegehumor also released their own parody of the song, using lyrics making fun of the song's mostly-meaningless lyrics.

One Week also appeared in Digimon: The Movie, American Pie and 10 Things I Hate About You