At this time last year, movie audiences were looking ahead to a holiday season dominated by “Harry Potter” and “The Lord of the Rings.” This year, they are looking forward to one dominated by “Harry Potter” and “The Lord of the Rings.”

On the surface, it’s déjà vu. But there are significant differences this time as the films square off. The “Harry Potter” series is moving into darker territory to attract a slightly older, teenage audience, and there is speculation in Hollywood that the “Lord of the Rings” series will supplant “Harry Potter” as the season’s box-office champion.

While the two movie series feature wizards and elves and other fantasy elements, they are really quite different and have appealed to subtly different audiences. The first “Harry Potter” was a classic family film, drawing in children and their parents, as well as enough from other demographic groups to create a hit. “The Lord of the Rings: Fellowship of the Ring,” the first in the trilogy, was an action epic that played most strongly to males in their teens and 20’s.

“Harry Potter and the Sorcerer’s Stone,” the first installment in what Warner Brothers hopes will be a multifilm franchise drawing cash into many AOL Time Warner divisions for years to come, made $318 million in United States theaters after opening last November.

“The Fellowship of the Ring” — an expensive gamble on which executives at New Line Cinema, also part of AOL Time Warner, practically staked the future of the studio — was more of a question mark before its opening. But the film was a box-office and a critical triumph, making $313 million in United States theaters and earning 14 Oscar nominations.

This year, the best guess from Wall Street analysts, professional box-office watchers and Hollywood executives — inside and outside the two studios — is that “Harry Potter and Chamber of Secrets” (opening on Nov. 15) and “The Lord of the Rings: The Two Towers” (Dec. 18) will dominate the holiday season, taking in at least $600 million between them in the United States, and twice that much overseas. But many expect “Lord of the Rings” to beat “Harry Potter” this year.

“I think people liked the first `Harry Potter’ movie, but they didn’t love it,” said one rival studio executive. “And I think it’s going to show at the box office.”

Another top studio executive, who also insisted on anonymity, put it this way: “Last year, I took my kids to see `Harry Potter.’ The curiosity factor was so high. I wanted to see it, too. This year, I’m dropping them off at the theater.”

Jessica Rief-Cohen, an entertainment analyst at Merrill Lynch, said that even if audiences were not as blown away by the first “Harry Potter” as they might have been, the series remained hot. “I thought the first movie was O.K., though the book was better,” she said. “But it’s going to be a monster hit, no matter how you look at it.”

Warner Brothers executives say their research shows that anticipation for the second “Harry Potter” film is just as high as it was for the first and carries to all ages.

“You just have to look at all the buzz around when J. K. Rowling will release the upcoming fifth book in the series and you can see that interest in the series is as intense as ever,” said Dawn Taubin, the president of domestic marketing at Warner Brothers. The next book, “Harry Potter and the Order of the Phoenix,” is expected next year.

Ms. Taubin dismissed any idea that the lack of a new “Harry Potter” volume in bookstores this year might have dampened interest in the series. “Last year, when there was a new book out, it became almost a whole year of `Harry Potter’ hype,” she said. “This year, we’re it.”

Whether the second “Harry Potter” does as well as the first — which had a $90-million opening weekend — will depend on many factors, including competition from family-oriented films like “Santa Clause 2” (opening on Nov. 1), “Treasure Planet” (Nov. 27) and “The Wild Thornberrys” (Dec. 20).

“I think certainly the issues for `Harry Potter’ and `Lord of the Rings’ are different than they were a year ago,” said Russell Schwartz, New Line’s president for domestic marketing. “Last year, it was all about `Harry Potter’ being the 800-pound gorilla, and it certainly delivered like that at the box office, if not with the critics. With `Lord of the Rings,’ no one really knew what to expect, so we had the great element of surprise and a kind of wow factor. This year, we both have to live up to what we did last year.”

The game of box-office expectations can drive movie studio executives crazy. “Star Wars: Episode II — Attack of the Clones” made $302 million in American theaters last summer, a substantial sum for any film. But expectations for the lucrative series were so high that when rival “Spider-Man” made even more ($404 million), some people in Hollywood considered “Star Wars” a box-office disappointment.

On Wall Street and among merchandisers, opinions differ about which film will end up on top, though there is unanimity that “Lord of the Rings” and “Harry Potter” will each rank among the two biggest hits. Either way, it is good news for AOL Time Warner, which could use some good news.

Other potential holiday hits include “Die Another Day,” a James Bond movie; sequels like “Star Trek: Nemesis” and “Analyze That”; and unknowns like “Catch Me If You Can,” a Steven Spielberg film starring Leonardo DiCaprio and Tom Hanks. They are expected to do well, though not as well as “Harry Potter” and “Lord of the Rings.”

Warner Brothers executives also point to differences between the first “Harry Potter” film and the second — differences that should be apparent to anyone studying the posters and billboard that have begun to appear. The young heroes in the posters look older, tougher and a little more determined. The one featuring Daniel Radcliffe as Harry shows him grimly wielding a gleaming sword covered in archaic runes, an image that seems borrowed from “The Lord of the Rings” and calculated to appeal to that trilogy’s older demographic.

“The campaign is a bit edgier, a bit darker,” Ms. Taubin said, in keeping with the more action-packed nature of the second installment.

And while Warner Brothers acknowledges that its family film will not deliver the violent thrills that might appeal to an older action audience, it says it hopes that more viewers between the ages 12 and 16 might be lured to theaters.

Last year, the mantra at Warner Brothers about how to handle the first “Harry Potter” film was “less is more.” The idea was to avoid pushing so hard to wring cash out of the first film that it put a bad taste in the mouths of parents and threatened the series’ long, lucrative life, so merchandising licensing was modest for such a major film.

This year, the game plan is to do more of the same, and to not get so transfixed on expectations or on out-performing either the first “Harry Potter” film or the latest “Lord of the Rings” installment that it harms the series’ long-term potential.

And the mantra this year?

“If it ain’t broke, don’t fix it,” said Diane Henry, who manages the “Harry Potter” brand for Warner Brothers.