The two-story structure fire in a house off campus was part of NIU's Greek Row of fraternity houses.
Unconfirmed reports indicate 12 people occupy the house. No one was seriously hurt.
The fire caused heavy damage and the students living there have been displaced.
DeKalb Fire Chief Bruce Harrison says a fire broke at the Omega Delta house. He says about 13 people were inside, including one who jumped out a second story window.
Harrison says one person was taken to a hospital with non-life-threatening injuries.
He says the NIU is working to find alternate housing for the fraternity's residents.
The Associated Press contributed to this report.