Diana Lynn Ossana (born August 24, 1949) is an American writer who has collaborated on writing screenplays, teleplays, and novels with author Larry McMurtry since they first worked together in 1992, on the semi-fictionalized biography Pretty Boy Floyd.
She attended Eastern New Mexico University, where she double majored in English and political science.
Ossana first read the Annie Proulx short story "Brokeback Mountain" in the October 13, 1997 issue of The New Yorker magazine.
They wrote Proulx asking her for an option to the short story in order to write a screenplay.
As a producer, Ossana joined cast and crew during the three months of shooting in Canada.