Abstract: A transportable animal enclosure assembly including opposed longitudinal sidewall assemblies each having a respective upper portion adapted to constrain sideways movement of the upper body portion of an animal being transported and a base wall extending between and laterally beyond the upper portions and being accessible to the animal transported. One or both sidewall assemblies preferably include a lower portion that slopes inwardly from the base wall to the upper portion. The transportable animal enclosure preferably includes adjustable rear support for supporting the rump of the animal and an adjustable chest restrainer for restraining the animal against the rear support.