Bergwijn scored eight goals during his spell at Tottenham
The 24-year-old Netherlands international, who previously played for Ajax at youth level, has signed a five-year contract.
Bergwijn scored eight goals in 81 appearances for Spurs after joining from PSV Eindhoven in January 2020.
"It is indicative of Steven's ambition that he chose to make the step to Ajax," said head coach Alfred Schreuder.
"He is a player with many qualities. He has enormous drive and is also very goal-oriented. Of course, I am happy that we were able to sign him, he adds new quality to our team."
The transfer fee is not only a record for Ajax, but also for any club in the Eredivisie.
"Dear Spurs fans, thank you for all the great moments and memories," Bergwijn said on Instagram.
"It was an honour to have been part of this beautiful club."
-- Courtesy of BBC Sport