The present invention relates to a holding device (100) for a light source (200), comprising a first portion (110) and a second portion (120). The first portion and the second portion extend at least partly in a common plane. The second portion is movable relative to the first portion from a first position, before insertion of the light source, in which the first portion and the second portion form a slit (130) for receiving the light source, and to a least a second position, after insertion of the light source, in which the second portion clamps the light source in the slit. Further, a lighting assembly and a display unit comprising such a holding device and a light source is disclosed. The holding device comprises fewer parts and is easier to manufacture as compared to prior art devices.