An angle-adjustable night lamp assembly includes an electrical plug unit, which includes housing having a stepped rear coupling portion and an electrically insulative locating block tightly fitted into a front opening of the electrically insulative plug housing to hold first and second metal conducting blades and a grounding prong, a lamp socket unit for holding a low-voltage lamp bulb and transferring electric current from the electrical plug unit to the low-voltage lamp bulb for causing the low-voltage lamp bulb to emit light, and a collar configured subject to the configuration of the stepped rear coupling portion of the electrically insulative plug housing and coupled to the stepped rear coupling portion and affixed to the lamp socket unit to secure the lamp socket unit to the electrical plug unit and to allow adjustment of the angle of the lamp socket unit relative to the electrical plug unit.