A leveling block for a wall construction system includes an upper surface, a lower surface, and a wall extending at least partially between the upper and lower surfaces and defining a leveling block void. A leveling plate engages the lower surface wherein the leveling plate includes a bore for receiving a threaded bolt having a contact surface and the threaded bolt extends into the leveling block void. The threaded bolt is adapted to be threaded to a desired position relative to the leveling plate to permit the contact surface to be positioned at a desired vertical position relative to the lower surface of the block such that the upper surface of the block is disposed substantially in a particular orientation when the block is placed on a surface.