Abstract: An adaptor assembly for mounting auxiliary tools and attachments on vehicles includes a plate having a rectangular tubular mounting sleeve extending at right angles from one side thereof and a pair of receiving channels defined by parallel spaced apart sidewall members extending from the other side thereof. The receiving channels receive and engage the mounting blades of a conventional vehicular snow plow hitch, so as to support the rectangular mounting sleeve in substantial alignment with the longitudinal axis of a vehicle. The mounting sleeve, thus securely attached to the vehicle, allows auxiliary apparatus or "tools" having rectangular mounting "prongs" to be quickly and easily attached to and separated from a vehicle in place of a snow plow, without precluding rapid repositioning of a snow plow when desired.