The Sum 41 star changed his name to Deryck Jason Lavigne Whibley after the pair married in 2006. They went on to split in 2009, and divorce a year later (10), but the musician only filed a petition to legally remove her name in 2013.
A Los Angeles judge granted the request in court on Thursday (12Jun14), according to Tmz.com.
Lavigne wed Nickelback frontman Chad Kroeger last year (13), while Whibley is currently engaged to Ariana Cooper.
The name change comes as Whibley is recovering from a near-fatal health scare earlier this year (14), when his liver and kidneys collapsed after years of heavy drinking.