The Leaving Cert exams have been postponed until late July or August.
Junior Cycle exams have been cancelled for this year, and will be replaced with school-based exams in the new school year.
State exams typically take place in June - but there had been growing concerns about whether they could take place as normal due to the ongoing school closures caused by the coronavirus crisis.
Today, Education Minister Joe McHugh confirmed schools will remain closed until further notice.
A new timetable for the Leaving Cert exams, meanwhile, will be confirmed in early June.
Minister McHugh said: “The final arrangements for the exams, the exam centres, social distancing and other measures will all be determined by the State Examinations Commission (SEC) on foot of public health advice in June.
“Students and their families have been seeking clarity. Today’s announcement addresses that.
"It also provides them with several weeks’ of advance notice to prepare for the examinations. I hope it helps to alleviate some stress being experienced by students and their families at this time."
He said he's not in a position to be able to say when students who have had their Leaving Cert delayed will be able to start third level.
The State Examinations Commission has said it's "making every effort to run the examinations as close to normal as possible" later in the summer, stressing that officials will continue to follow all public health advice.
The ASTI and TUI teachers' unions today said they'll now consider the Government's decision to delay the Leaving Cert exams.
They say they "understand the decision to defer" and welcomed the fact that the exams are still set to go ahead.
In a joint statement, the unions said: "We are conscious of the enormity of the challenges facing our society now, and we are appreciative of the work done by all concerned to meet these challenges.
"The executive committees of the two Unions will meet remotely this evening to see how best to proceed, and we will not be making further comment until after these meetings have taken place."
Meanwhile, the Association of Community and Comprehensive Schools, (ACCS) Education and Training Boards Ireland (ETBI), Joint Managerial Body (JMB) and National Association of Principals and Deputy Principals (NAPD) also issued a joint statement - saying they 'appreciate the clarity' brought by today's announcement.
The organisations suggested exam students should take a "complete break from their studies in this Easter period so that they can return refreshed and renewed".