In a statement posted on the band's official website, lead vocalist George Pettit announced the decision after two members quit - guitarists Dallas Green and Wade MacNeil.
The band are planning a final tour in their native Canada and "several special releases" to celebrate their 10th anniversary.
Announcing the break-up, Pettit revealed his disappointment at the outcome, commenting:
Was the break up amicable? Not really. Was it necessary? Probably. Regardless, the members of this band are my family and I wish them nothing but good fortune.
He added that the future for himself and other members Chris Steele (bass) and Jordan Hastings (drums) was "largely unwritten", adding:
Replacing one guitar player/singer/writer was something we thought was possible, but replacing two would run the serious legacy of what we achieved.
Green announced his intentions to quit a year ago but stayed on to complete a late 2010 tour of Europe, Australia and Canada. He released his third album with solo project City And Colour earlier this year - scroll down and click below to see an NME clip of the making of 'Little Hell'.
Meanwhile, MacNeil recently left the band to focus on other projects.
Alexisonfire released their self-titled debut album in 2002 and went on to release three more studio LPs - 'Watch Out!', 'Crisis' and their final LP, 2009's 'Old Crows/Young Cardinals'.
They also released an experimental EP, 'Dogs Blood', last year.
I will leave you with some of their best work... 'This could be anywhere in the world' from the album 'Crisis'.