Abstract: An adjustable socket has a body, a connecting segment and an adjusting segment. The body has a proximal end, a distal end, a mounting hole, at least one adjusting recess and a through hole. The mounting hole is formed through the body. The at least adjusting recess is formed on the body. The connecting segment is mounted on the proximal end of the body. The adjusting segment is mounted on the distal end of the body and has a stationary clamp, an operating element and an adjusting clamp. The stationary clamp is formed on and protrudes from the body and has a guiding hole and two clamping faces. The operating element is rotatably mounted in the mounting hole and has a mounting rod and a worm wheel. The adjusting clamp is connected to and engages the operating element, faces the stationary clamp and has an engaging protrusion, multiple engaging teeth and two clamping faces.