British Columbia Supreme Court Justice Alison Beames found Deborah Ashton innocent, saying there wasn't enough evidence to convict her of any of the five sexual assault counts prosecutors had brought against her, the Canadian Broadcasting Corp. reported.
Ashton cried and her supporters cheered when the verdict was announced, the CBC said.
The former Vernon school teacher left the courthouse without commenting to reporters but the news network said she later thanked her supporters in a posting on Facebook.
"This acquittal means a great deal and the gratitude I have for the people who chose to look beyond the surface conclusions of more than one imperfect system can't be easily communicated," Ashton wrote. "Again, thank you to those who have quietly and steadfastly supported me and my family. We are forever grateful."
It was the second trial for Ashton, who was alleged to have started having sex with the seventh-grader in 2002 when he was 12 years and she was 37. The first trial ended in a mistrial in 2011.
The alleged victim had testified he and Ashton had engaged in sex acts during most of their 230 intimate encounters. A friend of the boy testified he had seen them cuddling in a sleeping bag and her husband told of their deteriorating marriage.
Ashton's attorney called the allegations "character assassination" and said there were inconsistencies and gaps in the alleged victim's testimony.