Maines and Pasdar, who tied the knot at A Little White Wedding Chapel in Las Vegas in June 2000, share two sons: Jackson Slade, 16, and Beckett Finn, who turns 13 next week.
This is Maines' second divorce, after her first marriage to her college boyfriend, musician Michael Tarabay. The couple filed for divorce nearly two years after exchanging vows, citing irreconcilable differences.
Pasdar, who is best known for his role as Nathan Petrelli on the NBC series Heroes, met Maines in 1991 at the wedding of Maines' Dixie Chicks bandmate Emily Strayer to her ex-husband, Craig Robinson.
ET has reached out to Maines and Pasdar for comment.