At least 2,100 schools have shut their doors in North Kivu and Ituri provinces since January due to conflict, the UN's children's agency UNICEF stated.
Some 1,700 of those schools have closed due to persistent insecurity, linked to armed groups controlling surrounding areas.
Nearly 300 schools are being used to house displaced people, and 119 schools have been attacked by militias, according to UNICEF.
The education of around 750,000 children has been affected, the agency said.
Dozens of armed groups roam eastern Congo, many of which are a legacy of regional wars that flared during the 1990s and 2000s.
In North Kivu, M23 rebels have captured swathes of territory since taking up arms again in late 2021, displacing hundreds of thousands of people.
Some 240,000 children live in displacement camps near the province's capital Goma, and do not attend school, UNICEF said.
Neighboring Ituri province is also plagued by armed groups, suffering regular attacks by the Islamist-aligned Allied Democratic Forces militia, among others.
DRC Conflict Closing Schools: UNICEF
FILE: School children in Goma DRC, close to conflict zones where insurgents such as the M23 operate.. Taken Oct. 12, 2020.
KINSHASA - Rampant insecurity in eastern DRC is having a devastating impact on education, the United Nations said on Wednesday, interrupting schooling for nearly 750,000 children in the turbulent region.