Christopher Nolan's script for his mind-bending heist thriller Inception faces competition from boxing biopic The Fighter, Black Swan, and indie dramas The Kids Are All Right and Please Give for the 'Original Screenplay' prize.
For 'Adapted Screenplay', Sorkin's Social Network - based on Ben Mezrich's book The Accidental Billionaires - is up against 127 Hours, I Love You Phillip Morris, The Town and True Grit.
The Writers Guild Awards will take place on February 5.
The WGA movie nominations in full:
Black Swan (Mark Heyman, Andres Heinz, John McLaughlin)
The Fighter (Scott Silver, Paul Tamasy, Eric Johnson, Keith Dorrington)
Inception (Christopher Nolan)
The Kids Are All Right (Lisa Cholodenko, Stuart Blumberg)
Please Give (Nicole Holofcener)
127 Hours (Danny Boyle, Simon Beaufoy)
I Love You Phillip Morris (John Requa, Glenn Ficarra)
The Social Network (Aaron Sorkin)
The Town (Peter Craig, Ben Affleck, Aaron Stockard)
True Grit (Joel Coen, Ethan Coen)
Enemies Of The People (Rob Lemkin, Thet Sambath)
Freedom Riders (Stanley Nelson)
Gasland (Josh Fox)
Inside Job (Charles Ferguson, Chad Beck, Adam Bolt)
The Two Escobars (Michael Zimbalist, Jeff Zimbalist)
Who Is Harry Nilsson (And Why Is Everybody Talkin’ About Him)? (John Scheinfeld)