The court said its ruling was based on the state's failure to fully fund the 2008 School Funding Reform Act.
Justice Jaynee LaVecchia said the state's cuts to education funding violated the state Constitution.
"The schoolchildren who comprise the plaintiff class have been denominated victims of a violation of constitutional magnitude for more than 20 years," the opinion said. "Remedial orders were imposed to provide the education funding and services required to ameliorate the class' constitutional deprivation."
State officials asked the court two years ago to remove an order that required additional funding in the poor districts. The Supreme Court granted the state some relief -- additional expenses could have been much larger -- but said the state still would have to achieve parity funding in the poor districts.
The court majority said the Legislature's appropriations power under the Constitution did not relieve the state from coming up with the SFRA funding.
After the ruling, Gov. Chris Christie told a news conference, "I intend to comply with the Supreme Court's order. The constitutional ball is now in the Legislature's court," nj.com reported.