Various embodiments, aspects and features of the present invention encompass an expandable pet tunnel. It is envisioned that embodiments of the solution for an expandable pet tunnel may be constructed from any material suitable for a given application, although a preferred embodiment may be constructed from kraft paper. An exemplary embodiment may be constructed of a relatively thick paper and reside in either a collapsed state or an expanded state. When in the collapsed state, the exemplary embodiment may take the shape of a square. When in the expanded state, the exemplary embodiment may take the shape of a rectangular tube or tunnel that is open at either or both of its ends. When transitioning from the collapsed state to the expanded state, the exemplary embodiment may expand “accordion-like” according to a series of gussets or folds in the side walls of the embodiment.
