Singh, 20, has been rewarded for an impressive season in the Portuguese second tier after netting 11 goals and registering four assists in 35 appearances, helping Braga B narrowly avoid relegation.
The club confirmed the promising forward has been promoted to the first team, which earned UEFA Europa League qualification after a fourth-place finish behind Sporting Lisbon, Benfica and champions FC Porto.
"SC Braga announces the extension of the contract for Luther Singh, who is now committed for another five seasons, until 2022/23," read a statement on the club's website.
"Singh will join the main team in the start of the new pre-season, with a view to the 2018/19 season."
Singh has also been included in Stuart Baxter's latest Bafana Bafana squad participating in the upcoming COSAFA Cup in Polokwane.