Abstract: The present invention provides an extendible trailer generally consisting of three trailer sections arranged in side-by-side relation. The two outside trailer sections are connected to the central trailer section and are movable relative thereto along an axis that extends transverse to the longitudinal axis of the trailer. Two pairs of lead screws respectively interconnect the two outer trailer sections to the central trailer section, and a drive chain and cogged drive wheel assembly interconnects the two lead screws connected to each trailer section. By rotating any one the lead screws, the drive chain and cogged drive wheel assembly effectively moves the corresponding outer trailer section either toward or away from the central trailer section, thereby decreasing or increasing, respectively, the effective width of the trailer.