The 56-year-old, who returned for a second spell in 2022 having left the team in 2020 amid the COVID-19 pandemic, has managed a record-breaking 104 games for his side.
"This is a role that means a great deal to me," he said.
"I continue to believe strongly in the potential of this group of players and the direction we are moving in. There is a lot of work ahead, but I am excited by the future."
O'Neill first took charge of Northern Ireland in 2011 and oversaw their qualification for Euro 2016 - the nation's first major international tournament in 30 years - where they were knocked out in the last 16.
He had also been appointed interim Blackburn Rovers manager in February, balancing the role alongside his Northern Ireland duties, but it was confirmed earlier this month that he would not take that job on a permanent basis.
Northern Ireland also missed out on a place at the World Cup after a 2-0 defeat by Italy in a UEFA play-off semi-final in March, ending their hopes of qualifying for the tournament for the first time since 1986.
Irish FA President Conrad Kirkwood praised O'Neill's impact and said his contribution has been significant to the team.
"I am delighted that he will continue that work into the future and I look forward to more memorable achievements for the team," he said.
Northern Ireland face Guinea in a friendly on June 4 before travelling to France as part of preparations for the UEFA Nations League, which begins in September.