A legal petition filed Monday in Los Angeles County Superior Court states Jolie wants to change the 3-year-old boy's name so that it will include "the last name of her partner," Brad Pitt, and be the same as that of the couple's other children.
The petition was first reported by the syndicated television program "The Insider."
Jolie traveled to Vietnam last month to adopt Pax from a Ho Chi Minh City orphanage. The actress filed adoption papers as a single parent since she and Pitt are not married.
The pair's other three children are 5-year-old Maddox, who was adopted from Cambodia; 2-year-old Zahara, who was adopted from Ethiopia; and daughter, Shiloh, who was born to the couple last May.