A child from St Patrick's School in Blanchardstown, Dublin, was approached directly outside the grounds by a teenager who offered sweets and encouraged the little one to go with him.
The letter, sent just hours after the incident occurred yesterday, mentions that the child "responded appropriately and was thankfully unharmed."
Police and teachers have been notified but the school have asked parents to play their own part in teaching children about the possible dangers of interacting with strangers.
"I would ask you to re-inforce the two rules regarding strangers with your child," the letter reads. "1. Never go anywhere with a stranger. 2. Never take anything from a stranger."
The message, signed jointly by the junior and senior school principals, mentions that teachers had also been advised to teach "the appropriate Stay Safe lessons" as a result of the incident.
Local councillor David McGuinness said that adults in the neighbourhood would be playing their part in ensuring the road directly outside the school was supervised at busy times from now on. "There will be adults going back and forth, past the school and people should be vigilant in the wider community... We all have a role to play in community safety and community policing."
Do you highlight the importance of "stranger danger" with your child?
