It's alleged that Piotr Zaloba had a sexual relationship with the girl between Feb. 1 and March 8 of this year.
The 27-year-old was on a temporary contract and teaching Grade 9 at an Edmonton Catholic school.
Joan Carr, superintendent of the Edmonton Catholic School Board, said the teacher was suspended last week when the allegation surfaced.
She said she was personally "heartbroken and devastated" by the news.
"We have launched our own internal investigation ...." she told a news conference Monday. "We wish to assure our parent community that our schools are safe places."
Letters were being sent home to students and their parents asking them to come forward if they have similar allegations.
"The safety of our students is always our first priority," said the letter. "Please use this as an opportunity to discuss this incident with your child."
Insp. Dave Spiers said police continue to investigate the case.
"Any time there's a person in a position of trust that's alleged to have committed a sexual offence with a child, there is a possibility of other victims."
Zaloba is charged with sexual assault, sexual interference, invitation to sexual touching and child luring.
He is to appear in court April 15.
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