A horse boot includes a shell for the hoof and a gaiter for the pastern. The shell has a sole, an upper, a tongue, and an elastic component for tightening the upper and the tongue around the hoof of the horse. The gaiter is releasably attached to the upper so as to extend around the rear of the shell and is wrapped around the pastern of the horse immediately above the hoofs front hairline and below the fetlock to function as a barrier against the entry of debris into the shell. The gaiter provides an additional anchor to retain the shell in place under extreme conditions of use. The releasable connection to the shell allows replacement of the gaiter when worn out.
