Every integrated post-primary, one in three Catholic schools and all but five in the state-controlled sector stand to benefit from the government-backed initiative.
The high volume of eligible schools – 123 out of 147 – has sparked concerns that reading, writing and counting skills of secondary children is worse than was thought.
A total of 150 recently graduated teachers, who are without permanent employment, are to be given two-year contracts.
They will then deliver one-to-one tuition to pupils who are not projected to get C grades in their maths and English GCSEs. They are expected to be in post from September.
Post-primary schools identified as eligible were selected using a combination of academic performance and level of entitlement to free school meals.
The criteria for the project were developed to target those pupils most in need of support. It is hoped this will improve equity in the education system and close the gap between the most disadvantaged pupils and their more affluent peers.
Extra support, for example, is being targeted at schools with high free school meal entitlement; therefore almost every non-selective school will be able to avail of a teacher.
The amount of teaching support each school will receive will vary according to enrolment and performance.
Schools will be required to produce a plan outlining how they will achieve the best outcomes for the pupils identified as requiring additional support.
“The number of schools included does not reflect a failure to address poor literacy and numeracy levels,” a Department of Education spokesman said.
“Rather it demonstrates the real commitment of the Executive to support further educational improvement.
“It will build on the continuing rise in the proportion of children leaving school with five good GCSEs.”