It happened just before 4am on FM 529 at Greenhouse.
Four people were inside the car at the time. The two front passengers were pulled from the vehicle and had to be transported to the hospital. Officials said their injuries are not life-threatening.
The two other passengers and the four firefighters in the truck were not hurt.
Investigators said the Cy-Fair Volunteer Fire Department truck was responding to a call, but it did not have sirens or lights on at the time of the accident.
The crash remains under investigation.