In her decision, the judge said the plaintiffs - a group of U.S.-based WeChat users - had raised serious questions about whether the order threatened their First Amendment rights, and that a ban would place significant hardship on the 19 million people who use the app daily in the U.S.
Citing national security issues, the Commerce Department on Friday had issued restrictions against WeChat, owned by Chinese tech giant, Tencent.
The order - set to go into effect Sunday evening - required Apple and Google to remove WeChat from their app stores.
The judge's ruling also blocks the government's order that would have barred other transactions with WeChat in the U.S., which could have dramatically damaged the app's usability for current American users or potentially made it unusable altogether.
The app, which has more than 1 billion users world-wide, is popular among Chinese students, Americans living in China and some Americans who have personal or business relationships in China.
