Door stopper for a sliding door assembly, comprising - a mounting body for mounting the door stopper in a running rail of the sliding door assembly; - a first resilient detaining element which is at least partly elastically deflectable with respect to the mounting body for keeping a carriage of the sliding door assembly which is rollable in the running rail in an end position and which is arranged in such a manner that, viewed in the fitted position of the sliding door assembly, the spring force thereof is substantially directed towards a first longitudinal side of the carriage, - and a second resilient detaining element which is at least partly elastically deflectable with respect to the mounting body for keeping the carriage in the end position and which is arranged in such a manner that, viewed in the fitted position of the sliding door assembly, the spring force thereof is substantially directed towards a second longitudinal side of the carriage, opposite the first longitudinal side; wherein the first detaining element and the second detaining element are arranged at a distance apart, in such a manner that when the carriage is being held, this carriage extends partly between these detaining elements (6, 7), wherein the detaining elements (6,7) are configured as a leaf spring, wherein the detaining elements (6, 7) form part of the same leaf spring, which is folded to essentially form a U-shape, so that the first leg of the U-shaped leaf spring forms the first detaining element and the second leg of the U-shaped leaf spring forms the second detaining element, and in that each leg (6, 7) is provided with a bend in order to enable a corresponding part of the carriage to engage behind it in order to secure the carriage and wherein the door stopper comprises adjustment means (13, 12) for adjusting the position of the detaining elements (6, 7) with respect to the mounting body, characterised in that the adjustment means (13, 12) are configured to act on each detaining element (6, 7) on its side facing away from the side with which the detaining element (6, 7) is provided for acting on the carriage in order to detain it, and in that the adjustment means (13, 12) comprise a virtually U-shaped adjustment element, wherein the legs (14, 15) of the U-shaped adjustment element diverge from each other increasingly further towards their free end, wherein a first leg of the U-shaped adjustment element acts on the first leg of the leaf spring, at a fixed distance from the free end of said leg of the leaf spring, and a second leg of the U-shaped adjustment element acts on the second leg of the leaf spring, at a fixed distance from the free end of said leg of the leaf spring, and in that said adjustment element is displaceably arranged with respect to the leaf spring, so that the legs (14, 15) of the adjustment element act on the legs (6, 7) of the leaf spring at a smaller or greater distance from the free ends of the legs (14, 15) of the adjustment element, in such a manner that the legs (6, 7) of the leaf spring are brought closer together or moved further apart, respectively. - a mounting body for mounting the door stopper in a running rail of the sliding door assembly; - a first resilient detaining element which is at least partly elastically deflectable with respect to the mounting body for keeping a carriage of the sliding door assembly which is rollable in the running rail in an end position and which is arranged in such a manner that, viewed in the fitted position of the sliding door assembly, the spring force thereof is substantially directed towards a first longitudinal side of the carriage, - and a second resilient detaining element which is at least partly elastically deflectable with respect to the mounting body for keeping the carriage in the end position and which is arranged in such a manner that, viewed in the fitted position of the sliding door assembly, the spring force thereof is substantially directed towards a second longitudinal side of the carriage, opposite the first longitudinal side;