"If they don't shape up, I would withdraw from the WTO," Trump told the news agency, describing the agreement to set the organization up as "the single worst trade deal ever made".
Trump, who has previously criticized the WTO's dispute settlement system as being unfavorable to the US, said Washington had "rarely won a lawsuit" there although things began changing last year.
"In the last year, we're starting to win a lot," he said.
"You know why? Because they know if we don't, I'm out of there." China, which is currently embroiled in a trade war with the US, joined the WTO in 2001 -- a move which US Trade Representative Robert Lighthizer has described as a mistake.
Trump made the threat as Washington presses challenges at the WTO against trading partners that have fought back against tariffs on importers that were imposed by the Trump administration.