Roman Wladimir Jackiw (/ r oʊ ˈ m æ n dʒ æ ˈ k iː v / ; Ukrainian : Роман Володимир Яцків, romanized : Roman Volodymyr Yatskiv ; November 8, 1939 – June 14, 2023) was a Polish-born American theoretical physicist and Dirac Medallist.