The fairytale fantasy drama's co-creator confirmed the news on his Twitter page on Thursday evening (May 10).
"It's official -- #OnceUponATime has been picked up for season 2," he wrote.
"Thank you all so much for watching, we're beyond thrilled to continue on!"
Sitcom Suburgatory and mystery drama Revenge - which also debuted this season - have also been picked up again, Deadline reports.
Additionally, long-running series Grey's Anatomy, Castle, Modern Family and The Middle will also be recommissioned.
Revenge star Emily Van Camp tweeted that she "couldn't be happier" about her programme's renewal, while Castle's Seamus Dever congratulated cast and crew on a fifth season of the show.
Once Upon a Time recently enjoyed a surge in viewers to 8.8 million in the US following a series low of 8.2 million on April 1.
The show premiered on Channel 5 in the UK at the start of April.
ABC will officially confirm its programming slate for the new season at its upfronts presentation on Tuesday, May 15.