Quetzalcoatlus had an extremely long neck, a big head with a long pointed toothless beak, a short tail, a comparatively very small torso, and long limbs with which it was extremely capable both on the ground and in the air. As an azhdarchid, Q. northropi was one of the largest pterosaurs to ever exist.
Quetzalcoatlus northropi, the more popular of the two, was estimated to stand at around 5 meters (~16ft) tall, and is known from very fragmented fossil material.
Q. lawsoni, its smaller and more complete relative, stood at around 2.5 meters tall, and has far more complete fossil material. Most reconstructions of Q. northropi are based on Q. lawsoni.