An adjustment device for adjusting a position of at least one light module in a housing of a headlight, with a rotary member for at least indirectly transmitting a rotary motion to the at least one light module, wherein the rotary member at least at one point is guided through an opening in the housing and wherein for sealing the housing against the rotary member, an elastic sealing member is provided against an annular surface bordering the opening, which bears against the housing. To reduce the friction between the sealing member and the annular surface, the sealing member comprises a non-elastic annular element which is provided for abutment against the annular surface.