A connector position assurance device, an electrical connector and an electrical connector assembly which provides proper connector position assurance of a connector assembly of small size. The connector position assurance device has a base portion, a first beam and a second beam. The first and second beams extend from the base portion. The base portion includes a latch engagement protrusion. A first beam has a first connector engagement protrusion and a second beam has a second connector engagement protrusion. The first and second connector engagement protrusions are resiliently actuated as the plug is mated to the header. The first and second connector engagement protrusions and the latch engagement protrusion cooperate with the plug when the plug is fully mated to the header to prevent the inadvertent removal of the plug from the header.