Gibbons, who won Olympic -78kg silver at London 2012 last summer, was bidding for world glory in the same category in the city where the next Games will be held.
Gibbons got off to a positive start in Brazil beating Anar Seitimova of Kazakhstan by waza-ari and yuko in the first round but then met her match in Viktoriia Turks.
The Ukrainian lost their last match at the Moscow Grand Slam, where Gibbons went on to win bronze, but history didn't repeat itself in round two at the World Championships.
Turks caught her and held her down for ippon while fellow Brit Natalie Powell, also fighting in the -78kg category, lost by the same method to Anamari Velensek of Slovenia in round one.
Both will now quickly turn their attentions to the Rijeka Grand Prix in Croatia from September 14-15 but still Gibbons' disappointment at her world outing was clear.
"I'm gutted. I could have been world champion, but I'm not. I just got caught by Turks and it ended my championships," said Gibbons.
"I wish I could restart the day but that's not how judo works. Now my focus is on the next Grand Prix in Croatia and the Grand Slam events coming up."
Britain now face the possibility of leaving Rio without a medal just over a year after winning two at London 2012, Gibbons' silver and bronze from the now retired Karina Bryant.
Sally Conway was due to fight on the same day as Gibbons and Powell in the -70kg but withdrew the night before due to a hip injury with Sarah Adlington and Philip Awiti-Alcaraz the last Brits up.
© Sportsbeat 2013