Leigh and Baumbach married in 2005 and are the parents of an infant son. They collaborated on the 2008 film "Margot at the Wedding."
The couple's breakup was reported Tuesday by Radar Online. Irreconcilable differences were cited as the cause for the split.
UsMagazine.com said Leigh's publicist declined to comment on the story.
Leigh has starred in "Fast Times at Ridgemont High," "Single White Female" and "Dorothy Parker and the Vicious Circle."
Baumbach's films include "The Life Aquatic with Steve Zissou," "The Squid and the Whale" and "Fantastic Mr. Fox."