These are in addition to the tragic deaths of Erin (13) and Shannon (15) Gallagher in Donegal and Ciara Pugsley (15) in Leitrim.
Both deaths are understood to have occurred in the Cork area.
Suicide Aware's Patricia Behan revealed the deaths as it launched a partnership with internet security firm TrendMicro and garda community officers to tackle online abuse.
"The aim is to highlight the dangers of cyber-bullying to mental health and to educate young people about the safe use of social media," she said.
Under the programme, a dozen gardai will be trained by TrendMicro in internet security and social media usage.
Volunteers will then go into schools and help educate teachers, students and parents about the dangers.
Gardai said the programme will initially target transition year students but, if successful, will be rolled out to all secondary school classes.
The programme was unveiled after a major anti-bullying conference heard Facebook warn that it will show zero tolerance to abusive online postings.
Ireland is one of a number of EU countries considering the introduction of 'E-IDs', electronic identity tags that will allow online users to be sure about the age of the person they are interacting with.
The safety initiatives came after Junior Minister Shane McEntee took his own life last December following a campaign of social media abuse.
Two weeks ago, the Herald revealed that a 16-year old Cork teen had also been subjected to a campaign of abuse.
The Church of Ireland Bishop of Cork, Cloyne and Ross, Dr Paul Colton, ended his Twitter account after what he described as 'depressing' attacks by anonymous internet 'trolls'.
The cyber messages are understood to have included scathing attacks against the Christian churches in Ireland.