Reth Suzana, a 16-year-old semi-finalist from the last season of The Voice Cambodia—a wildly popular spinoff of the U.S. television competition—released one of her first singles last week as Phnom Penh was preparing for one of its favorite new holidays.

“Christmas is Back,” sung in a mix of English and Khmer, begins true to form, with the familiar festive sound of sleigh bells and Suzana crooning “Christmas, Christmas, oh, Christmas tree.”

When the chorus hits, however, things start to slip away from tradition: “Christmas is back, so how old are you?/Christmas is back, someone may ask you/Don’t care and let it go/Just know you’re beautiful/Christmas is back….”

For Suzana, and many other Cambodians who have embraced the imagery and traditions of the holiday, Christmas is more of a mood and a style, the history and meaning of which is, well, meaningless.

Asked what Christmas meant to her, Suzana replied: “I don’t really know.”

“My family all celebrate Christmas since my brother and sister live abroad,” she said in an interview this week. “We love Christmas a lot.”

Her siblings, who live in Australia, introduced the Buddhist family to the holiday, which has its roots in Christianity, but celebrates consumerism as much as anything else.

Hang Meas Film Production, which produces The Voice Cambodia, has been releasing original Khmer Christmas songs for eight or nine years, said In Tito, a company coordinator.

The success of the tunes, he said, was a testament to Cambodians’ love of the holiday season.

“They are celebratory songs, and in Cambodia, festivals are always popular,” Mr. Tito said. Christmas time, he added, was just another excuse to have a party.

“Khmer like to celebrate Christmas now,” he said. “We just want to celebrate, you know.”

At Home of English International School in Phnom Penh, classrooms and hallways this week were decked out in enough tinsel and fake snow to trick any Westerner into thinking they had walked into a school in their hometown. In the reception room, a Christmas playlist blared over the PA system.

Although the founder of the school was a Christian, Christmas time at the institution—which caters largely to the Cambodian middle class—was purely about the aesthetics, the songs and the presents, said Mina Cailles, director of the kindergarten and playschool programs.

“We don’t try to push anything Christian-related,” Ms. Cailles said. Every time December comes around and the Christmas trees go up, she said, many of the students aren’t really sure what they are celebrating.

“It’s hard to explain it, because if you explain the real meaning of Christmas then you have to talk about nativity and all this,” she said.

“So it’s mostly Christmas trees and Santas.”

Even there, though, the school does not promulgate the holiday’s fantastical version of a portly, red-robed Mr. Claus who flies around the world dropping off gifts to good kids and lumps of coal to bad ones.

“We don’t have Santas anywhere—that’s our way of trying to not mislead them,” she said.

“He’s just a Christmas figure.”

Ms. Cailles, a Filipino who has been living in Cambodia since 2005, said that although the festivities here lack the nativity scenes and big Church events of her predominantly Catholic home country, Christmas was clearly becoming a very popular affair.

On Thursday, students voted on the best-decorated classroom door. Entrants ranged from a giant snowman made from white-painted tin cans to an elaborate village complete with fairy lights. On Friday, they held a Christmas fair with games, photo booths and crafts creating a carnival atmosphere.

Panya Mong, a sixth-grade student at the school, said he was about 9 years old when he first learned about the holiday, but still did not have a clear idea of what it was all about, apart from the holiday being a time to spend with family and friends.

“I like that we all get to stay together,” he said.

Sokheang Somol, 14, said her family had started celebrating Christmas at home by hanging wreaths and exchanging gifts—but you won’t hear any Christmas songs at the Somol household.

“We only do that at school,” she said.

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