17 is a song recorded by Avril Lavigne for her self-titled fifth studio album. It was written by Lavigne, Jacob Kasher, and Martin Johnson. When the demo for the song leaked in full, it received critical acclaim from critics upon its leak. On October 25, 2013, the studio version of the song leaked onto the Internet.
Lavigne debuted the song at a performance at the Viper Room in 2013. Lavigne told the audience that she chose to play the song "17" that night and that she wanted them to listen very carefully because they had never heard it before. She added that "I wrote this song about...Duh, being 17. Okay, so, that's pretty much it." Lavigne later spoke to Idolator about the song: "There's a lot looking back on this album. I have a song called '17', and that is a year for me that my career really started, and I experienced a lot for the first time. I find myself speaking to my friends or my family or in interviews, saying, like, 'Oh, back when I was 17....' So, I wrote a song called '17'. It's cool because the second verse in that song talks about 'stealing beers out of the trailer park' [laughs], and my brother and I actually did that, so the first time I played the song for my brother, I was like, 'Do you remember that?' He was like, 'Oh my God, that's so crazy!'"
Lyrically, the song speaks of a relationship when Lavigne was only seventeen that she wishes she could go back to.
The song received mixed to positive reviews from critics. While some found the song to further exemplify Lavigne's refusal to grow up, a common theme throughout the album that was heavily criticized by critics, many found it to be refreshing and reminiscent of Lavigne's previous work. Perez Hilton wrote that it would remind listeners of why they loved Lavigne when she emerged on the music scene in 2002. Sam Lansky of Idolator wrote that the song was as good as, if not better than, the album's lead single, "Here's to Never Growing Up". He further called it "wistful, nostalgic, and gloriously emotional". Lansky ended his review by praising the production, the detail of the lyrics (which he compared to the lyric "take off all your preppy clothes" from "Complicated"), the chorus, and Lavigne's refusal to grow up (something reminiscent of "Here's to Never Growing Up"). Jessica Sager of PopCrush noted that "the song is poppy and was performed with an acoustic guitar; the bridge features an infectious 'whoa-oh,' and the melody of the entire track is designed to get stuck in your head for days."
Some compared the song to Taylor Swift's song "22".