Franz Moritz Graf von Lacy (English: Francis Maurice de Lacy; Russian: ????? ???????? ?????, tr.
Boris Petrovich Lassi; 21 October 1725 – 24 November 1801) was a Baltic German-born Austrian military leader, he was the son of Count Peter von Lacy and was a famous Austrian field marshal.
He served during the reign of Maria Theresa and was a close friend to Joseph II, Holy Roman Emperor, becoming one of the latter's advisers.