An adjustable socket having a housing with a longitudinal axis. A collar is couplable to and movable along the housing. The collar's lower end is bevelled. A plurality of circumferentially spaced apertures extend through the housing. A jaw is mounted in each aperture for slidable, radial movement through the aperture. Each jaw has a flat inward face and a bevelled outward face. The jaws are biased radially outwardly away from the axis. Rotation of the collar around the housing in a first direction forces the collar's bevelled end against the jaws' bevelled faces, forcing the jaws radially inwardly and forcing their inward faces against a fastener located between the inward faces. Rotation of the collar in the opposite direction allows the jaws to be biased radially outwardly to release the fastener.