Abstract: A camper trailer adapted to be converted from a retracted, trailable condition in which it has normal length and width and reduced height which does not obstruct the rear view of the driver of the towing vehicle and a power-erected, livable condition in which it has normal length and height and expanded width whereby the amount of living space within the erected camper is increased substantially over the amount of living space available in a camper trailer having the corresponding normal length, width and height. A feature of the invention involves the provision of extension assemblies which are mounted in each side of the camper trailer and are slidable to an extended position to increase the width of the camper and substantially increase the living space therewithin.