An adjustable wrench has a wrench body, a clamping element, and a ratcheting jaw. The wrench body has a handle, a head, and a thumbscrew. The head is formed on the handle and has a connecting block, a fixed jaw, a curved slot, two pin holes, a positioning pin, a mounting recess, two pivot holes, and a sliding slot. The clamping element is connected to the wrench body and has a sliding bar, a ribbed slab, and a movable jaw. The ribbed slab is formed on the sliding bar and is mounted in the sliding slot. The movable jaw has an engaging surface and a positioning block. The ratcheting jaw is a curved block capable of sliding forward and retracting backward inside the curved slot and has two mounting boards, a receiving recess, an engaging surface, an abutting surface, an engaging protrusion, a holding recess, and an elastic element.