Eustachius Benedictus de Lannoy (also sometimes called 'Captain De Lannoy') (30 December 1715 – 1 June 1777, Udayagiri Fort) was a skilled military strategist and commander of the Travancore Army, under Maharaja Marthanda Varma. The Dutch force had to engage the Travancore Army; however, was defeated at the Battle of Colachel by the Travancore army. His role as military commander of the Travancore army was instrumental in the later military successes and exploits of Travancore under Maharaja Marthanda Varma and Dharmaraja.