The flames broke out around 4 a.m. at the two-story home on 73rd Street in North Bergen.
Firefighters say the residents were able to get out safely.
Two firefighters were being treated for burns. One was transported to St. Barnabas Hospital, while the second was transported to Hoboken Hospital.
The other two suffered smoke inhalation and were treated at the scene.
The fire was put out around 6 a.m., and there is significant damage to the home.
There is no word on how it started, and the investigation is ongoing.