Brunette Amelia Tat, 27, faces up to 20 years behind bars after the illegal relationship with her pupil aged between 13 and 15.
She first made contact with the youngster outside of school by contacting him on Instagram and Snapchat and asking personal questions.
She then asked the boy to “stay late and help her after class” before the pair had sex.
The disgraced teacher continued to text the youngster, before they romped again at Tat”s flat in Lynchburg, Virginia, after she picked him up from a baseball game.
But the pair were caught out after the victim”s mum found messages from Tat on his phone and discovered “something going on”, prosecutor Darby Lowe said.
She had been working as a science teacher at the teen”s school when the relationship happened in 2015.
By the time the teen boy”s mum went to police she had moved to another school.
She was charged with three counts of carnal knowledge — sexual intercourse — with a minor and one of taking indecent liberties with a child.
During a plea deal at Albemarle Circuit Court on Friday Tat admitted two counts of carnal knowledge.
She could be jailed for 10 years on each count and fined $200,000 (£160,000) when sentenced in May.