Lajos Thallóczy, (Also, Ludwig von Thallóczy, Ljudevit Taloci, born Lajos Stommer) (Budim, 8. December 1856. – Herceghalom, 1. December 1916.) was a Hungarian historian, archivist and high public servant.
His main interests were Bosnian history, especially genealogy, heraldry and biographies of prominent individuals from its medieval period. He published numerous Cyrillic and Latin charters, and also works about the duke Hrvoje Vukčić, history of Jajce and numerous other, Bosnia-related, subjects, with the main findings published in the book Studien zur Geschichte Bosniens und Serbiens im Mittelalter, published in Munich and Leipzig in the year 1914.
He died in a train accident while returning from the funeral of the emperor Franz Joseph I.