(277475) 2005 WK4, provisional designation 2005 WK4, is a stony, sub-kilometer asteroid, classified as near-Earth object and potentially hazardous asteroid of the Apollo group that passed Earth within 8.2 lunar distances on 8 August 2013. It was discovered on 27 November 2005, by astronomers of the Siding Spring Survey at Siding Spring Observatory, Australia.