The invention relates to apparatuses for a reversible pet spiral staircase. Embodiments of the invention comprise: a bottom tread storage platform member; a plurality of tread platform members, elevated above the bottom storage platform member; a center leg support member, and a plurality of outer leg support members, which support the tread platform members; and a helical skirt board railing member that supports the tread platform members and traverses the perimeter of the apparatus. Embodiments of the invention are capable of being configured in either the left-hand spiral configuration, or the right-hand spiral configuration. Embodiments of the invention allow the apparatus to be self-supporting; reversible; space-saving; compactable for storage; safe for pet elevation; easily assembled; reconfigurable; and environmentally safe.