Among the big winners was the sci-fi smash "Inception." It took home the best original screenplay award for writer Christopher Nolan.
"The Social Network" won best adapted screenplay for writer Aaron Sorkin.
The wins position the two writers as favorites in the same categories at the Oscars on Feb. 27.
In television, "Modern Family" was honored for TV comedy writing and the series "Mad Men" took home the WGA trophy for TV drama writing.