"Argo" screenwriter Chris Terrio shared the award with Antonio Mendez, the CIA operative who wrote the autobiographical "The Master of Disguise," and Joshuah Bearman, who wrote the Wired magazine article "The Great Escape" during the 25th annual awards program Saturday, The Los Angeles Times reported.
"Argo," directed by actor-director Ben Affleck, who portrayed Mendez in the movie, competed with "Beasts of the Southern Wild," "Life of Pi," "Lincoln," "Perks of Being a Wallflower" and "Silver Linings Playbook."
The "Argo" script also is nominated for the Writers Guild of America Award and the Academy Award.
Larry McMurty and Diana Ossana, adapted screenplay Oscar winners for "Brokeback Mountain," received the Scripter Literary Achievement Award, the Times said.
"Argo" is nominated for seven Academy Awards. It was named the best dramatic film and earned Affleck the director award at the Golden Globes, won Screen Actors Guild Award for ensemble; earned the top prize from Producers Guild of America Award and won the best director award from the Directors Guild of America.