The Oscar-tipped drama chronicles The Boston Globe's investigation into child abuse in the Catholic Church and features an all-star ensemble cast.
Other nominees included thrillers Bridge of Spies and Sicario, alongside rap biography Straight Outta Compton.
For best adapted screenplay, the writers of space adventure The Martian and female drama Carol earned nods.
The WGA picks five films for its best screenplay award. As expected, it favours heavyweight dramas but the guild also added romantic comedy Trainwreck to its shortlist, alongside Straight Outta Compton.
Written by Amy Schumer, the film features an ensemble cast, including Tilda Swinton and Brie Larson, star of another Oscar-tipped drama, Room.
Written by Josh Singer and Tom McCarthy, Spotlight has already had a strong showing during awards season, including success at the National Society of Film Critics awards, where it won best film of the year.
It also won best film at the Los Angeles Film Critics Association awards last month. It has also been nominated for a Golden Globe for best picture.
Sicario, which stars  Emily Blunt and Benicio del Toro, was also on the list of nominees for the best film of 2015 award from the American Society of Cinematographers (ASC).
The movie tells the story of a conscientious FBI agent enlisted by a government task force to foil a brutal Mexican drug cartel.
The film was also among the contenders for this year's Palme d'Or at the Cannes Film Festival.
Elsewhere, the ASC again tilted in favour of dramas, with Bridge of Spies and Carol also on their best film list, as well as hard-hitting revenge western The Revenant, starring Leonardo DiCaprio.
The Writers Guild of America will present its awards on 13 February while the American Society of Cinematographers will hand out its honours the next day.
Meanwhile, this Sunday sees the Golden Globe awards take place in LA, followed next week by the nominations for the Oscars on 14 January.
Spotlight is among the film's named on the The Writers Guild of America (WGA) shortlist for best screenplay.