A system and method for determining an orientation of a vehicle are provided. The system and method determine (with a sensor assembly disposed onboard a first vehicle) a direction in which a fluid flows within the first vehicle. The first vehicle is included in a vehicle consist with a second vehicle. The orientation of the first vehicle relative to the second vehicle is determined based at least in part on the direction in which the fluid flows within the first vehicle. The fluid may be air in an air brake pipe of the vehicle consist.