A Brisbane District Court jury took just five hours Thursday to find Amanda Louise Thompson guilty of one count of maintaining an unlawful relationship with a child between April 2003 and 2005.
During the 10-day trial, the court was told of the relationship that developed when Thompson was a teacher at a school south of Brisbane.
The student - who cannot be identified - was just 14 when Thompson embarked upon her seduction.
The court was told Thompson, from Boronia Heights, initially took the teenager under her wing when she discovered the student had an eating disorder.
Prosecutor Todd Fuller said the pair became firm friends, but that the relationship "spun out of control" over the next three years.
He said the pair quickly became inseparable and they would regularly stay the night at each other's house.
The court was told they also took holidays together and that Thompson showered the student with gifts and notes.
They also met regularly to engage in sexual activities that included Thompson penetrating the young student with everyday items such as a lollipop and a necklace.
The girl's mother gave evidence that she often saw them "cuddling", and that she repeatedly had to ask them to keep the door open when they were in her daughter's bedroom.
The student's friends also said they saw them engaging in "weird" behaviour in local parks and on a trip to the Royal Queensland Show.
Thompson was questioned by school authorities and police about the relationship, but repeatedly denied she had done anything wrong, AAP reports.
Her defence barrister, Mark Johnson, urged the jury to acquit his client, arguing the student's evidence was based on "pure fantasy".
Thompson's family wept as Thompson, remanded in custody, was led to the cells and told her they loved her.
She will be sentenced at a later date, after undergoing psychological and psychiatric assessments.