Her and Captain Phillips have won the main prizes at the Writers Guild of America (WGA) awards in the US.
Spike Jonze was the winner of best original screenplay for Her, which he also directed.
Captain Phillips - a film about piracy starring Tom Hanks - won writer Billy Ray best adapted screenplay prize.
The WGA awards are the last major leg in the Hollywood film awards calendar before the Oscars are handed out on 2 March.
Both Her and Captain Phillips are in the running for best picture at the Academy Awards, but neither are considered front runners for the accolade.
But the guild, which held ceremonies in both New York and Los Angeles, has correctly predicted the screenwriting Oscars for eight of the past 10 years.
'An award for pain'
These were the first screenwriting awards for Jonze and Ray.
Jonze said: "It's a high honour coming from writers."
"I was thinking about how in a way it's like an award for pain. It's a specific pain that writers know and it's the highs and lows of sitting in there by yourself," he added.
Her, the tale of a man, played by Joaquin Phoenix, who falls in love with a computer-generated voice won best screenplay at last month's Golden Globes awards gala.
Ray, whose screenplay is based on the true story of a cargo ship hijacked by Somali pirates, said he owed a debt to Captain Richard Phillips.
"It's really Captain Phillips who wrote this story, I just wrote it down," he said.
Small screen hit Breaking Bad was also recognised, with screenwriting wins for best TV drama and best individual episode.