He meets Grindelwald in the *Fantastic Beasts* series, but not until the third movie, *The Secrets of Dumbledore*.
In the books, Harry learns about Grindelwald through:
* History of Magic classes: He learns about Grindelwald's rise to power, his rivalry with Dumbledore, and his eventual defeat.
* Albus Dumbledore: Dumbledore shares his memories of Grindelwald with Harry, helping him understand the threat he posed.
* Other characters: Some characters, like Newt Scamander, have personal experience with Grindelwald and share their knowledge with Harry.
The movies adapt this information, showing Harry learning about Grindelwald through various means, but he never actually meets him.