The utility model belongs to the technical field of vehicles, and discloses a seat back plate, a seat and a vehicle, the seat back plate comprises a back plate body, the back plate body is provided with a front side face and a back side face which are oppositely arranged in the thickness direction, the back side face of the back plate body is provided with an installation groove, and the installation groove is configured to contain a lamp source; or, a mounting hole penetrating through the back side surface is formed in the back plate body, and the mounting hole is configured to accommodate a lamp source. According to the seat back plate, the seat comprising the seat back plate and the vehicle comprising the seat back plate, sufficient light can be provided for drivers and passengers with reading requirements, the activity space in the vehicle is not affected, and the user experience feeling is good.