Eleven people were left wounded as their bus collided with a luggage transporter on Friday morning, seriously injuring both drivers and another passenger.
The bus was carrying 75 people from a flight from Barcelona on a loading area at the airport at around 8.50am when the collision occurred.
The flight with a total of 201 people had landed shortly before the crash, and the bus was transporting groups to the airport building.
Some passengers have been brought to hospital, according to police, and emergency workers are on the scene.
The bus crashed into the luggage vehicle as it tried to change lane, swerving after the crash into some scaffolding.
The bus driver had to be cut out of the vehicle by fire crews.
This is far from the first traffic accident at Frankfurt Airport, Germany's busiest air hub.
In 2014 a minibus crashed into a luggage transporter, injuring five people, one of them seriously.
In 2011 the driver of a shuttle bus drove into a group of airport employees, killing a 26-year-old.