Olympe Mancini, comtesse de Soissons (born 1639—died Oct. 9, 1708, Brussels) was the niece of Cardinal Mazarin and wife from 1657 of the Comte de Soissons (Eugène-Maurice of Savoy).
Olympe Mancini had a brief affair with the young king Louis XIV when she was in her teens and took part in the amorous intrigues of the French court up to 1680, when she fled the country after being charged with complicity in the Affair of the Poisons (a scandal involving widespread murder and purported black magic). The Habsburgs’ great general, Prince Eugene of Savoy, was her son.