The 18-year-old made his La Liga debut as a late substitute in the 1-1 draw at Levante on January 19, and has also appeared in the UEFA Champions League and Copa del Rey for the Catalan giants.
The Cameroonian has had a buyout clause of €12 million written into his deal, and has recently been linked with a loan move to Premier League outfit Aston Villa.
And Dongou was delighted to extend his deal with the Spanish champions.
He told the club's official website: "It's a very important day in my career.
"I'm very happy. The two most important days were the first day I arrived (at the club) and the day I made my debut at Camp Nou.
"I am very excited to continue working and improving."
Dongou's compatriot, defender Macky Frank Bagnack, has also extended his deal until June 2017.
The 18-year-old has made 14 appearances for Barcelona B this term.
"I am delighted to renew for the best team in the world. I am very happy," he commented.
Barcelona currently sit top of La Liga with 54 points from 21 matches.
TALENTSPOTTERWhy you need to know... Jean Marie Dongou
