Light guide for a motor vehicle lighting device (10, 60, 70), the light guide being flat and being delimited by a first wide light guide surface and a second wide light guide surface opposite thereto, and a parallelization portion, a deflection portion adjoining in the beam path and an outcoupling portion adjoining said deflection portion, the parallelization portion having a light introduction region and being designed to parallelize the light fed in through the light introduction region, the outcoupling portion having a narrow light outcoupling surface extending between the wide light guide surfaces (16, 18), and the deflection portion having a deflection surface which is formed on a narrow side surface extending from the parallelization portion to the outcoupling portion and being configured to deflect the light coming from the parallelization portion to the outcoupling portion, the deflection surface comprising a plurality of reflection surfaces for reflecting light beams to the outcoupling portion, and a plurality of offset surfaces, between each two reflection surfaces at least one offset surface being arranged such that the reflection surfaces are arranged so as to be offset in a step-like manner along the course of the deflection surface from the parallelization portion to the outcoupling portion, the first wide light guide surface and the second wide light guide surface being curved in the region of the deflection portion such that the stepped deflection surface extends along a deflection guide curve which is curved with respect to two different spatial directions, characterized in that the light introduction region is plate-like and in each case is curved in the cross sections so as to be perpendicular to and in parallel with the beam path and blends continuously into a plate-like and planar light guide region of the parallelization portion such that a light bundle which initially extends divergently in the light introduction region is formed into a parallelized light bundle which extends in the planar light guide region. and a parallelization portion, a deflection portion adjoining in the beam path and an outcoupling portion adjoining said deflection portion, the parallelization portion having a light introduction region and being designed to parallelize the light fed in through the light introduction region, the outcoupling portion having a narrow light outcoupling surface extending between the wide light guide surfaces (16, 18), and the deflection portion having a deflection surface which is formed on a narrow side surface extending from the parallelization portion to the outcoupling portion and being configured to deflect the light coming from the parallelization portion to the outcoupling portion, the deflection surface comprising a plurality of reflection surfaces for reflecting light beams to the outcoupling portion, and a plurality of offset surfaces, between each two reflection surfaces at least one offset surface being arranged such that the reflection surfaces are arranged so as to be offset in a step-like manner along the course of the deflection surface from the parallelization portion to the outcoupling portion, the first wide light guide surface and the second wide light guide surface being curved in the region of the deflection portion such that the stepped deflection surface extends along a deflection guide curve which is curved with respect to two different spatial directions, characterized in that the light introduction region is plate-like and in each case is curved in the cross sections so as to be perpendicular to and in parallel with the beam path and blends continuously into a plate-like and planar light guide region of the parallelization portion such that a light bundle which initially extends divergently in the light introduction region is formed into a parallelized light bundle which extends in the planar light guide region.