Boyd, who also was a child actor, died of cancer at a Santa Monica convalescent hospital, said Eleanor Pillsbury, a longtime friend.
Three weeks after the yuletide kiss-and-tell was released, the song was No. 1 on the Billboard charts. It sold 2 million records in less than 10 weeks. Tens of millions of copies of the much-covered song written by Tommie Connors have been sold over the decades, according to the Allmusic online database.
It has been interpreted by such artists as the Jackson 5, John Mellencamp and Amy Winehouse. Molly Bee was also 13 when she later had a hit warbling about the unlikely pair kissing underneath the mistletoe last night." Bee died last month at 69.
Although it came to be regarded as a holiday classic, the ditty about a child who can't understand why Mommy is cheating on Daddy with Santa Claus caused controversy in some quarters when the original featuring Boyd's childish treble was released.
The Catholic Church condemned the song for implying even a tenuous link between sex and the religious holiday, and radio stations in several markets banned it. The ban was lifted after the 13-year-old Boyd appeared before church leaders to talk about the lyrics.
Recorded at the urging of Columbia record executive Mitch Miller, the tune made something of an overnight national musical figure" of the vocalist, a freckle-patch" who lived in Van Nuys, Time magazine reported in 1952.
Lyrics such as She didn't see me creep/Down the stairs to have a peep" weren't quite up to the title-line," the magazine huffed. Even the young singer was surprised by the song's success.