The crash happened at Evanton at about 17:20 on Saturday. The fire service and the air ambulance was sent to the scene.
The occupants of all three vehicles were injured, but the extent of their injuries was not known, police said.
A spokesman added: "Inquiries are ongoing into this matter and no further witnesses are sought at this time."
Several people have been injured in a three-car collision on the A9 near Dingwall in the Highlands.