The forward has agreed a deal that takes his contract to the summer of 2026.
Crucially, it includes a release clause to the value of £51.5million, something that could be of interest to a number of clubs in the Premier League.
Nkunku enjoyed a wonderful campaign last term, scoring 20 goals and providing a further 13 for his teammates.
As a result Manchester United and Chelsea were heavily linked with a move for the player but, after penning a new deal, it seems that they will need to wait before making a move.
Speaking to the club's official website after signing a new contract, Nkunku said: "I'm pleased to continue wearing the RB Leipzig shirt.
"After our great achievement in winning the DFB-Pokal, it remained clear that my story here isn't over yet - we want more!
"I was really impressed with the club's efforts to keep me, so a big thanks goes to those responsible for the trust in me and especially to [CEO] Oliver Mintzlaff, with whom I was always in close contact.
"RB Leipzig have made a name for themselves on the international stage in recent years and have shown time and again that we can compete for titles.
"We want to build on that going forward and go one step further."