The suit accuses Gawker Media of disseminating copies of Tarantino's unproduced screenplay, "The Hateful Eight."
Tarantino told Deadline.com last week he planned to make the western his next project, then decided not to make the movie after someone made copies of the script and distributed it through Hollywood.
He said one of the six people he trusted with the script had let someone else see it.
After the story of the leak broke, Gawker's Defamer website posted a link to the 146-page script under the heading, "Here Is the Leaked Quentin Tarantino Hateful Eight Script."
"Gawker Media has made a business of predatory journalism, violating people's rights to make a buck," the Hollywood Reporter quoted Tarantino's lawsuit as saying. "This time, they went too far. Rather than merely publishing a news story reporting that plaintiff's screenplay may have been circulating in Hollywood without his permission, Gawker Media crossed the journalistic line by promoting itself to the public as the first source to read the entire screenplay illegally."
Gawker's representative told THR the company hasn't received the lawsuit yet.