The Cabinet has approved the extension of child benefit to 18-year-olds from 1 May for those in full-time education or who have a disability.
Minister for Social Protection Heather Humphreys said the measure will benefit families of 60,000 18-year-olds.
It was initially expected that the measure would be introduced in September of this year, however Minister Humphreys said that changes in IT meant that it can now happen from the beginning May.
Child benefit is paid at €140 per child per month, and the change is being introduced due to the significant number of 18-year-olds who are still in second level education and also as a measure to assist families with the rise in the cost of living.
Ms Humphreys will seek to introduce the change by amending a social welfare bill which is due before the Seanad later this week.
Speaking as he arrived for the Cabinet meeting, Taoiseach Leo Varadkar said the move is "in recognition of the fact that it is increasingly normal for 18-year-olds to be in school or even just to start their first years in college while they are 18."
He added that bringing up a teenager was expensive, and the child benefit payment would not be means tested.
Louise Bayliss, founder of SPARK, welcomed the move saying there was a policy gap that was preventing economically disadvantaged children from remaining in school in their last year, which tends to be one of the most expensive years.
Speaking on RTÉ's Today with Claire Byrne, Ms Bayliss said: "It's a game changer".
She said that up to now, purely for financial reasons, children in their last year of school dropped out and went to services like YouthReach, and that this fed into inter-generational poverty.
