Abstract: A horse boot for resilient engagement about the hoof wall and adjacent hoof structure. A boot wall extends upwardly from the perimeter of a boot sole and includes a flexible rear wall portion of generally concave-convex shape. The rear wall portion is flexible to permit manual repositioning thereof downwardly about the rear edge of the sole to open the boot for passage of the horse's hoof into place. A raised rear portion of the rear wall contributes to hoof engagement. The boot sole may be perforate to receive horseshoe projections.