The Prince of Wales said the end to J.K. Rowling's series of books on the boy wizard's adventures was "awful", the Daily Mirror reported.
The eighth and final film adaptation Harry Potter and the Deathly Hallows Part 2 released last week.
Charles was in Salcombe, Devon, accompanied by his wife, the Duchess of Cornwall, when he made the comment to children from a primary school.
Sue Warne, a school teacher, said: "He (Charles) asked them whether they liked reading, whether they liked Harry Potter and whether they had read the books and seen the films."
"He said how awful it was that there were no more Harry Potter books to come."
