Radu R. Rosetti (April 1 [O.S. March 20] 1877–June 2, 1949) was a Romanian general and military historian.
Born in Căiuți, Bacău County, he was part of the old boyar Rosetti family; his father, Radu Rosetti, was a writer. He attended primary school in his native village and then studied at the National College in Iași. After taking classes at the school for bridges and roads, Rosetti graduated from the military school for artillery and engineering in 1899, and in 1906 completed the Higher War School. During World War I, he was chief of the operations bureau for the general staff. In this position, he objected to the numerous promotions made two days before the fall of Bucharest to the Central Powers, ostensibly to raise officer morale. He believed promotions for their own sake cheapened the meaning of rank and eroded respect for the hierarchy. Although he too was promoted, he noted in his diary that he was not at all pleased with the honor. Rosetti later commanded an infantry regiment. Wounded in August 1917 during the Battle of Mărășești, he was awarded the Order of Michael the Brave, third class.
After the war, he was successively named military attaché in London, brigadier commander and head of training courses for high-level officers. In 1924, he was advanced to the rank of general. Continuing to deplore the large number of promotions made in the triumphant mood that followed the creation of Greater Romania, Rosetti soon resigned from the army. He authored books on military history and theory, some of them works of pioneering research. He headed the National Military Museum, an institution he had said from 1914 should be established. Elected a corresponding member of the Romanian Academy in 1927, he advanced to titular status in 1934 before being stripped of membership in 1948 by the new communist regime. He headed the Romanian Academy Library between 1931 and 1940, assuming the role at the suggestion of his retiring predecessor Ioan Bianu. As director, he oversaw construction of a new headquarters, completed in 1938.