Sybille Bianca Giulietta Eysenck (/ˈaɪzɛŋk/ EYE-zenk; née Rostal; 16 March 1927 – 5 December 2020) was a British personality psychologist and spouse of psychologist Hans Eysenck, with whom she collaborated as psychologists at the Institute of Psychiatry, University of London, as co-authors and researchers.