Natalina D'Addario, of suburban Kensington, was teaching in the northern suburbs when she began a sexual relationship with the 15-year-old.
The 37-year-old Italian teacher today pleaded guilty in the Victorian County Court to three counts of sexual penetration of a child in her care.
Chief Crown prosecutor Jeremy Rapke QC told the court D'Addario performed oral sex on the student in her car on three occasions between May and July last year.
The liaisons started after D'Addario told him off for calling her sexy in front of other students.
She told him to "reserve it for one-on-one occasions" and when asked by the student, she agreed she also found him sexy, Mr Rapke said. She then started sending him romantic and sexual text messages, he said.
One day after school, D'Addario picked the student up in her car and they drove to a location at Ascot Vale where she performed oral sex on him. During a police interview, D'Addario said she felt coerced into giving the student oral sex and did not want to.
Her barrister Robert Richter QC told the court his client was a lonely, loving, vulnerable, depressed person at the time of the offences.
He said she felt shame and remorse, and pleaded guilty at the earliest stage. She had had an exemplarily character before this offence, Mr Richter said. Judge Roland Williams will sentence D'Addario later today.