Eugéne-Hyacinthe-Marie-Joseph-Ignace de Lannoy, 5th Count of la Motterie, baron of Aix and Sombreffe (1684, Brussels – 10 September 1755) was a functionary in the Austrian Netherlands.
He was the son of François-Hyacinthe de Lannoy, 4th Count of la Motterie and Baron of Sombreffe, and Anne-Françoise of Gavre.
Claude de Lannoy, 1st Count of la Motterie was his great-grandfather.
He married Lambertine du Faign, Countess of Hasselt, lady of the Starry Cross.
He was succeeded by his son Chrétien de Lannoy, 6th Count of La Motterie.