Constantin Poenaru (April 8, 1842–1912) was a Romanian general. Born in Bucharest, Poenaru attended the local officers’ school from 1859 to 1861, followed by the École supérieure de guerre in Paris. A second lieutenant from 1861, he rose to captain in 1867 and to major in 1872, and commanded the military engineers’ battalion from 1872 to 1877. When the Romanian War of Independence broke out in 1877, he saw action during the Siege of Plevna. and Valter Mărăcineanu were under his command.