Andre Ladeiro (8), whose family are originally from Portugal, died five days after suffering critical injuries in a collision on Saturday morning in Carrigaline, Co Cork.
Savannah Barry Calvert (14) died after she was hit by a car in Limerick city centre on Wednesday evening.
Taoiseach Leo Varadkar expressed deep concern at the growing number of deaths on Irish roads.
The Road Safety Authority (RSA) has already met with garda chiefs to discuss the increase, with deaths now running at more than 30pc above 2019 levels.
A total of 108 people have died on Irish roads so far this year, 14 more than in the same period last year.
Moving tributes were paid to Andre, who was fatally injured while crossing the road near the Ballinrea roundabout in Carrigaline .
He was with one of his parents and his younger sibling at the time.
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He was rushed to Cork University Hospital (CUH) and then airlifted to Temple Street Children’s Hospital in Dublin with head injuries.
Despite efforts by doctors to save him, he died on Wednesday evening with his family at his hospital bedside.
He was a pupil at Owenabue Educate Together National School, where a spokesperson said everyone was “devastated by the tragedy”.
“Andre joined us in September 2020, the very first day the school opened,” they said.
“From the day he started his journey with us he brought joy into every room he entered. Andre was a bright, curious boy who, above all else, was unfailingly kind.
“Andre’s smile and personality lit up every room, and every person he met was better for having met him.
“We extend our deepest sympathies to his parents, Filipa and Cesar, his brother Tomas and all of Andre’s extended family and friends. You are all in our thoughts.
“Andre’s family have requested that we all understand their need for privacy at this difficult time.”
The school implemented its critical incident management plan, and psychologists from the National Educational Psychological Service (NEPS) are supporting and advising.
Andre died just days before he was due back in school. It is understood the family have lived in the Cork area for several years, and the child’s parents work locally.
Tributes were also paid to schoolgirl Savannah by members of her family on social media.
Denika Calvert said everyone was left heartbroken by the tragedy.
“I cannot believe it, my beautiful baby sister – why did it have to be you? What am I going to do without you? You are all I have,” she wrote.
Channelle Calvert described Savannah as a youngster whose smile brightened the lives of everyone she met.
“God, why did you have to take the most harmless child that would do anything for anyone. You did not deserve any of this – you are back with Nana Jackie now,” she wrote.
Gardaí in Limerick have appealed for information about the accident, which happened shortly before midnight near Limerick’s Bank Place.
A spokesperson said: “The pedestrian, a female youth in her teens, was taken to University Hospital Limerick with serious injuries, where she has since passed away.
“No other injuries to persons were reported during the course of this collision.”
