A safety belt system, especially for motor vehicles. The system includes a three-point safety belt, a self-locking belt reel-in mechanism mounted on a structural part of the vehicle, and a clamping mechanism for the belt strap of the safety belt. The clamping mechanism has at least one movable clamping jaw, and is movably disposed and guided on the structural part. A drive mechanism is provided for effecting movement of the clamping mechanism. To better adapt the geometrical path of the safety belt system to the body proportions of a strapped-in occupant, to thereby more reliably prevent endangering forward movement of the body of the occupant, the clamping mechanism is disposed, along with its drive, in the structural part of the vehicle in such a way that they are vertically adjustable. For automatic vertical adjustment of the clamping mechanism, an arrangement is provided which senses the position of the belt strap relative to at least one parameter of its functional connection with a strapped-in person, and which undertakes a comparison, with a fixed desired value, of the actual value of the belt strap position as determined relative to the at least one parameter to ascertain whether a deviation exists between the two values. The sensing and value-comparison arrangement initiates a vertical adjustment of the clamping mechanism when the ascertained deviation continuously exceeds a designated deviation between the desired value and the actual value.