A foldable trailer having a frame and platform which are laterally divided into a front, rear and central section, the axle of the trailer being secured to the central section. The central section is pivotally connected respectively to the front and rear sections so that the front and rear sections can fold up into storage positions normal to that of its central section. The front and rear sections are releasably lockable with the central section so that they are in the same plane as that of the central section during operative use of the trailer. An improved hinge is provided to permit tight fitting of the confronting surfaces of the sections when the sections are in position for operative use and to permit and unobstructed pivoting of the front and rear sections with respect to the central section when they are being folded into storage position. The trailer according to the present invention provides a sturdy platform during operative use, yet permits it to be collapsed for storage or transportation.