A Melbourne teacher who sexually assaulted two girls, including an intellectually disabled student, is free on bail as he fights a four-month jail term.

Richard Grabski, 34, was found guilty at trial of touching one girl on her vagina and the other on the thigh during separate incidents at a Sunshine secondary school in mid-2017.

The first incident occurred in 2016 when a Year 12 student attended an after-hours homework club at the library.

Maths teacher Richard Grabski leaves the Magistrates Court yesterday. Picture: AAP (Nine)

Grabski was suspended from teaching last year. He continues to maintain his innocence. Picture: AAP (Nine)

The 34-year-old assaulted the girl as he spoke to her about a mathematical problem, placing his hand up her skirt.

Grabski was found to have touched the first girl on her vagina for some minutes and afterwards told her it had to be a secret.

Seven months later, he struck again in the library, putting his hand under the uniform of a Year 11 student with an intellectual disability, who had sat next to Grabski while she worked on an origami project.

Grabski taught at Sunshine Secondary College in Melbourne's west. Picture: 9NEWS (9NEWS)

The offender then exchanged email addresses with the girl from the address "wantondesecration@yahoo.com.au".

In one email, Grabski asked to meet the girl in a science room: "Hi, meet after school tomorrow?"

Court documents also show he contacted his first victim using a school messaging system after she failed to attend classes in the days after the assault.

One of the victims told the court in a statement: "I felt scared, I didn't want him to touch me. I felt upset because he didn't let me go."

Richard Grabski has been bailed. Picture: 9NEWS (9NEWS)

In her victim impact statement, one of the girls said she felt "violated" and "scared" when Grabski touched her and sometimes felt unsafe at school after.

"I would like to put all of this and my school behind me and look forward to the future," the girl said, as read by prosecutor Mark Sontag.

Magistrate Jon Klestadt described Grabski's actions as a "gross" breach of the trust placed in him as a teacher and said such crimes can be difficult to detect.

"Perpetrators of this type of offending often rely on the vulnerability of their victims," Mr Klestadt said.

"And the reluctance that most, if not all, young people have in accusing their abusers because of the fear of retribution or just not being believed."

The offender targeted two girls. Picture: 9NEWS (9NEWS)

Grabski was found guilty of two counts of indecent acts with a child and today sentenced to four months’ jail. He will also be placed on the sex offenders register for the next 15 years.

He immediately lodged an appeal and was released on bail.