Karl von Mansfeld (1543 – 24 August 1595) was a German general during the Cologne War and the Ottoman-Habsburg wars.

Von Mansfeld was the son of Count Peter Ernst I von Mansfeld-Vorderort, born in present-day Luxembourg, and was educated in France. He entered the military of Philip II of Spain, and was appointed a general and an admiral in the navy of the Spanish Netherlands. He was sent to Hungary, where along with Count Mátyás Cseszneky he participated in the siege of Esztergom in 1595 during the Long War. He died shortly thereafter, probably of his wounds, in Komárom.^[1]

He married twice, first to Diane de Cossé and, second, to Marie Christine von Egmond, who died 1622.

She had, from her second marriage, a son, Alexandre de Bournonville Duc de Bournonville, Comte de Henin-Lietard (14 September 1585, Brussels, died 21 March 1656), and, probably with Mansfeld, a second son, Antoine III de Lalaing (born between 1588 and 1590 and died 26 September 1613), Count of Hoogstraeten, who married Maria Margaretha de Berlaymont, daughter of Claude Berlaymont, also known as Haultpenne.