Became engaged to Jennifer Aniston on his birthday, August 10, 2012.
Cousins are Marcel Theroux, a writer and Louis Theroux, the actor, writer and journalist who makes television programs for the BBC.
Academy Award-nominee (documentaries) Rachel Grady and her friend, Brooke Jones, took Justin Theroux to his first prom in Washington, D.C. and
Justin's journalist mother, Phyllis Theroux, reported on their date in the June 5, 1985 New York Times.
Nephew of Paul Theroux, author of many travel books.
Has a younger brother, Sebastian, born in 1989
His father is of half French-Canadian and half Italian descent. His mother has English, German, 1/64th Spanish, and distant Dutch, ancestry.