Geoffrey Lilley Smith (born 1955) FRS FMedSci FRSB is a British virologist and medical research authority in the area of Vaccinia virus and the family of Poxviruses. Since 1 October 2011 he is head of the Department of Pathology at the University of Cambridge and a principal research fellow of the Wellcome Trust. Before that, he was head of the Department of Virology at Imperial College London.