The invention provides a backlight module, a display module and a display device, so as to realize a narrow frame of the backlight module and enhance the overall strength of the backlight module to prevent problems such as fragmentation, abnormal sound and abnormal image. The backlight module comprises a back plate, a light guide plate, a light emitting light bar and a printed circuit board. The back plate comprises a bottom plate, a side plate and a top plate. The side plate is located between the bottom plate and the top plate. The top plate is used for carrying a display panel. The printedcircuit board is connected with the display panel, and is arranged in an accommodating space formed by the top plate, the side plate and the bottom plate. The light emitting light bar is disposed arranged in the accommodating space and is embedded in one side, which faces the light guide plate, of the printed circuit board. The printed circuit board is arranged in the accommodating space, and thelight emitting light bar is embedded in the side, which faces the light guide plate, of the printed circuit board. An external space occupied by the original printed circuit board is omitted. The vertical size of the backlight module can be reduced. Narrow frame setting is arranged. The overall strength of the backlight module can be enhanced to prevent problems such as fragmentation, abnormal sound and abnormal image.