By many measures, the “Harry Potter” series is the ultimate winner: It’s the most successful film franchise in box-office history, selling more than $5.8 billion in tickets worldwide. Audiences love it, returning seven times over the last 10 years to theaters to see the latest installment. But now, with the penultimate movie released last week and the final installment due next summer, the pressure is on the boy wizard to snare the one accolade that has eluded the series: an Oscar.

Is the prize the unattainable Horcrux, or can Harry and Co. conquer the academy?

That battle for Oscar recognition may be as epic as Harry’s quest to defeat Voldemort. Over the years, the Warner Bros. series has occasionally received nominations for categories such as art direction, costume design and visual effects, but the Academy of Motion Picture Arts and Sciences has never rewarded the series with a win.

Some Oscar consultants say it’s unlikely the academy will look seriously at this year’s film, “Harry Potter and the Deathly Hallows: Part 1” after snubbing the series for so long, and knowing that they have another chance next year.

But if director David Yates delivers a tour de force with “Harry Potter and the Deathly Hallows: Part 2” in July, the academy might take a closer look next season, essentially honoring the eight-picture series for its overall achievement.

It wouldn’t be the first time that a populist film with a literary history gets rewarded by the academy in its final incarnation. “The Lord of the Rings: Return of the King” took home 11 Oscars in 2004, including best picture and director, when voters acknowledged director Peter Jackson and New Line Cinema for the extraordinary wager they took by financing and filming the three films in the trilogy at once.

“With ‘Lord of the Rings,’ there was a huge risk involved, and it was the risk people rewarded,” said one veteran Oscar marketer who asked not to be identified. “With ‘Harry Potter,’ it would be the consistency of so many movies well done that would be rewarded. (The academy would be saying) ‘here’s your cherry to go on top of the gazillions of dollars you’ve made.'”

But unlike Harry Potter, the early installments in the “Lord of the Rings” series did win Academy Awards in categories including cinematography, makeup, original score, sound editing and visual effects. And all three were nominated for best picture.

A number of top Oscar consultants say they have heard that Warner Bros. is planning a massive campaign in Los Angeles, New York and London next fall for the final film, bringing out for the media and the voters all of the characters that have been killed off, a campaign that would essentially remind voters of the scope of the “Potter” series.

Warner Bros. declined to comment, saying that they do not reveal the details of their Oscar campaigns, especially for a film that’s not yet complete.

With “Lord of the Rings,” New Line had an advantage in high-profile writer/director/producer Jackson, whose distinct vision created an epic trilogy of story-telling.

The “Harry Potter” films, in contrast, had multiple directors, so its creative center is producer David Heyman. While regarded as highly proficient, he is not seen as an auteur, and that may count against the franchise when it comes to Oscar voters in the specific guilds.

The “Potter” films have had four directors: Christopher Columbus helmed the first two, Alfonso Cuaron and Mike Newell each directed one, and Yates led the last three into theaters.

With different directing styles came uneven reviews and “Harry Potter” never had the kind of endorsement from the critical community that “Lord of the Rings” enjoyed through its entirety.

“‘Lord of the Rings’ was extraordinarily reviewed, unbelievably reviewed, all three of them,” said Russell Schwartz, New Line’s former president of marketing who orchestrated the films’ campaigns. “‘Return of the King’ won the New York Film Critics Award,” he added. “That’s not going to happen with ‘Potter.'”

Of the seven “Potter” films released thus far, Cuaron’s “Prisoner of Azkaban” was the best-reviewed, according to Rotten Tomatoes’ Top Critics rankings. The most recent film received the second-worst reviews of the bunch, faulted for its slow pacing and lack of conclusion.

“The last one, if it stands on its own, will get the good marks for everything else by association,” Schwartz said. “It has to be as good as the best one.”

Until then, the studio is tasked with keeping “Harry Potter” in the minds of Academy Awards voters.

“They’ve done it right all the way through,” said Oscar consultant Melody Korenbrot. “It just depends on what else comes out. But this is a big boy now.”