Letourneau, 43, and Vili Fualaau, 22, have been in the spotlight since she was imprisoned in 1997. But when she was released last August, the couple - who have two daughters together - reunited.
Since then, details of their wedding have been closely guarded - except for a series of interviews by "Entertainment Tonight" and its sister TV show, "The Insider." The shows have exclusive rights to the nuptials. Show officials said they did not pay for the wedding.
Shortly after 10 p.m., Letourneau and Fualaau exchanged vows they had written themselves, said Janet Annino, ET's co-executive producer in Washington for the wedding.
The ceremony was at the Columbia Winery in Woodinville, about 20 miles northeast of Seattle, Annino said.
"Mary Kay was whisked out of the hotel to this venue under intense security," she said. "She arrived here with a sheet over her head. She had to lie down in the car coming in to avoid the paparazzi."
Letourneau's teenage daughter, Mary Claire, from her earlier marriage, was maid of honor. The couple's two daughters, Audrey, 8, and Alexis Georgia, 7, were flower girls.
The couple first met when Fualaau was in the second grade. Their relationship became sexual when he was 12 and she was a 34-year-old married mother of four, a teacher at a suburban elementary school.
Letourneau was pregnant with Fualaau's first child when she was arrested in 1997. She pleaded guilty to second-degree child rape and was sentenced to 7½ years in prison, with all but six months suspended.
Within weeks of her release, she was caught having sex with Fualaau in her car and ordered to serve the remainder of her sentence. She gave birth to the couple's second daughter while serving time.