The only child of the former Hollywood couple has previously been home-schooled.
E! News said Holmes, who was raised Catholic, recently enrolled Suri in the Convent of the Sacred Heart, the $38,000-a-year, all-girl school in Manhattan where pop star Lady Gaga, actress Jordana Brewster, heiress Nicky Hilton and author/attorney Caroline Kennedy once studied.
Cruise, who is a member of the Church of Scientology, and Holmes settled their divorce last week. Holmes moved in late June to end their five-year marriage.