This paper deals with a new seismic protection system for timber platform frame buildings, either for retrofit or for new construction. The system consists in connecting the timber frame to a steel framed structure that includes hysteretic energy dissipators designed to absorb most of the seismic input energy thus protecting the timber frame and the other steel members; alternatively, the system might contain other dissipative devices. The steel structure comprises horizontal beam-like elements, vertical column-like elements and chevron-like bracing members; the beam-like elements are steel belts embracing each slab of the building and the bracing members hold the energy dissipators. The steel structure is self-supporting, i.e. the timber frame is not affected by horizontal actions and can be designed without accounting for any seismic provision; in turn, the steel members do not participate in the main carrying-loads system. The timber-steel contact is even, smoothed and spread; it guarantees that the yielding of the dissipators is prior to any timber failure. This research belongs to a wider project aiming to promote the structural and constructional use of timber by improving the seismic capacity of wooden buildings; this research includes experiments and advanced numerical simulation aiming to derive accurate design criteria.