The invention provides a sealing structure for a vehicle lighting unit which can reliably prevent rolling-up of a sealing member. The vehicle lighting unit sealing structure includes a continuous sealing wall protruding from a rear surface of a housing of a rear combination tail lamp so as to surround bulb sockets supported by the housing, an engagement protrusion positioned outside the sealing wall, the engagement protrusion protruding from the rear surface of the housing so as to extend substantially parallel to the sealing wall, a sheet-like sealing member attached to an end of the sealing wall so as to cover the sealing wall, the sealing member having a slit through which the engagement protrusion extends to provide friction force between the slit and the protrusion, and a stud bolt, positioned inside the sealing wall, temporarily retaining the sealing member. The sealing member is sandwiched between the sealing wall and a lighting unit attachment wall portion of a vehicle body panel to seal a space inside the sealing wall.