Messages of sympathy are being collected in a book at Forest Hill Collegiate, where the 17-year-old went to school briefly before her disappearance in 2009.
Principal Peggy Aitchison sent an email to students this week encouraging them to attend a memorial for Makhniashvili or write comforting words to her family.
Though Makhniashvili's classmates have long graduated, she says the school has a special bond with the girl whose story captured national attention.
A visitation is scheduled this afternoon for Makhniashvili, whose remains were found late last month in a wooded area in north Toronto.
A private funeral service for relatives and guests is scheduled for Saturday afternoon.
Makhniashvili's father, Vakhtang Makhniashvili, has been denied permission to attend the funeral, but his lawyer says he is fighting the decision.
He is serving a six-year jail term after pleading guilty last year to three counts of aggravated assault after two separate stabbing incidents, one involving a neighbour and the other a couple who had posted his bail.
Mariam Makhniashvili had been in Toronto only three months, and in school only four days, when she went missing on Sept. 14, 2009.
"This young woman who went missing really was embraced by this city, in terms of the care and concern and worry and so on," Aitchison said.
"I think it speaks a lot to our collective humanity in this country that someone who is a stranger to the country, to people, that so many people in the country... cared about her and wanted the best outcome for her," she said.
The case baffled authorities for two and a half years, despite numerous tips and reported sightings from as far as Alberta.
The only real clue that emerged was the discovery of Mariam's backpack and some school books in a parking lot not far from her school the month after she went missing. Then, in late February, skeletal remains were discovered near Highway 401 and Yonge Street, not far from the highway overpass.
Police later confirmed the body was Makhniashvili's and said foul play wasn't suspected.
While they wouldn't go as far as ruling her death a suicide, police have suggested she may have been depressed.