A tubing string rotator for rotating a tubing string in a well having a downhole pump. The tubing string rotator includes a housing having a first portion and a second portion. At least the second portion of the housing is adapted to be operatively connected to the end of a length of the tubing string such that rotational torque applied to the tubing string through the operation of the pump is transferred to the second portion of the housing. The rotator further includes means to permit the controlled rotation of the second portion, together with the tubing string connected thereto, relative to the first portion of the housing when the ability of the first portion to rotate is retarded or eliminated, and when rotational torque is supplied to the tubing string through the operation of the pump.