The couple walked down the aisle this weekend in a private ceremony that took place in Italy.
"We are happy to confirm that Maggie and Peter were married on Saturday," their reps told E! News.
The vows were swapped in a quaint chapel in Brindisi before some three dozen guests, including the bride's brother, Jake Gyllenhaal, and his girlfriend, Reese Witherspoon.
This is the first marriage for both the 31-year-old Dark Knight-starring Gyllenhaal and her 38-year-old beau, whose credits include a Golden Globe-nominated turn in Shattered Glass (and one hysterical SNL skit).
The über-private couple have been together since 2002 and engaged since 2006. In October 2006, Gyllenhaal and Sarsgaard became first-time parents to daughter Ramona, now 2.