The fire crews were rushing to the scene of an accident on the B9006 Inverness to Nairn road shortly after 07:00 when the incident happened.
The Scottish Fire and Rescue Service said five of the eight firefighters had been taken to hospital in Inverness.
Their injuries are not believed to be life-threatening.
Two of the crew had to be freed from the wreckage by their colleagues.
An investigation is under way into the cause of the crash. It is not yet clear whether the engines collided or if the weather may have been a factor.
A spokesman for the fire service said: "At 07.03 on Saturday 6 February, Inverness control were advised of a road traffic accident on the B9006 at Cantraybruich. They subsequently dispatched two appliances from Inverness fire station to attend.
"At 07.16, while en-route to the incident under blue light conditions, both appliances left the road at Newlands of Culloden.
"Six crew members were able to exit the vehicles. Two crew members were, however, trapped inside an appliance for a period before being released by colleagues."
Fire service staff are at Raigmore Hospital in Inverness to provide support to the crew members and family and replacement engines have been drafted in to Inverness.
There are no reports of serious injuries from the initial road crash.
Five firefighters have been injured after two fire engines came off the road on the way to a crash near Inverness.