The move brings an end to a relationship that began in 2006, when Mbappe was still a teenager. Nike had made him one of the leading figures in its football marketing in recent years, particularly as Cristiano Ronaldo's career entered its later stages.
Mbappe said the switch represented another major change in his career.
"Once again it, football, has led me to one of the biggest changes in my life," Mbappe said on social media. "Now, I find myself surrounded by innovators who dream of the same things I do."
On is preparing to enter the football boot market in 2027 and has appointed former France international Thierry Henry as its director of football.
The company, which is backed by tennis great Roger Federer, is also looking to expand its presence in the Americas, where it generates more than half of its revenue.
Mbappe's departure follows Nike's recent loss of another high-profile young star, with Spain and Barcelona forward Lamine Yamal joining Adidas.
Nike thanked Mbappe for their long partnership.
"We are proud of what we achieved together on and off the pitch," the company said. "As he moves into the next phase of his career, we wish him continued success for what comes next."
Mbappe's move gives On a major name as it prepares to launch its first football boots and increases the brand's profile in the world's biggest sport.