The ban, which is set to take effect on January 1, 2024, will prevent downloads of TikTok in Montana and would fine any entity $10,000 per day for each time someone "is offered the ability" to access the social media platform or download the app. The penalties would not apply to users.
The five plaintiffs are all Montana residents who use the app for things like promoting a business, connecting with military veterans, sharing outdoor adventures or expressing their sense of humor.
They stated the ban would "immediately and permanently deprive Plaintiffs of their ability to express themselves and communicate with others."
They argued the state seeks to "exercise powers over national security that Montana does not have and to ban speech Montana may not suppress," stating the law violates their First Amendment rights.
"Montana can no more ban its residents from viewing or posting to TikTok than it could ban the Wall Street Journal because of who owns it or the ideas it publishes," the lawsuit said.
TikTok responded shortly after the governor signed the bill, saying Montana's ban "infringes on the First Amendment rights of the people of Montana by unlawfully banning TikTok," and said it will "continue working to defend the rights of our users inside and outside of Montana."
Judge Donald Molloy, who was appointed by Democratic President Bill Clinton in 1995, has been assigned the case, and "could issue an injunction keeping the ban from taking effect until legal proceedings are finished," said a Forbes report.
TikTok, which has over 150 million American users, has faced growing calls from U.S. lawmakers and state officials to ban the app nationwide over concerns about data privacy. In March, a congressional committee grilled TikTok CEO Shou Zi Chew about whether the Chinese government could access user data or influence what Americans see on the app.
TikTok has repeatedly denied that it has ever shared data with the Chinese government and has said the company would not do so if asked.