Stephen James Challacombe FRC(Path), FDSRCS, FMedSci, (born April 1946) is professor of oral medicine at King's College in London, best known for research in oromucosal immunology and for developing the Challacombe scale for measuring the extent of dryness of the mouth. He led the team that laid out research challenges of global health inequalities and oral health, particularly relating to the oral manifestations of HIV.