Romualdo Marenco (March 1, 1841 – October 9, 1907) was an Italian composer primarily noted for ballet music. Marenco started his musical career as a violinist in the Doria Theater in Genoa. His first composition was the ballet Garibaldi's Landing in Marsala. He was appointed the orchestral conductor for La Scala in Milan and also directed the ballet company there for seven years. His best-known ballets were written in collaboration with choreographer Luigi Manzotti during that period.
Marenco is best remembered for the ballet Excelsior, composed in 1881. Excelsior is a tribute to the scientific and industrial progress of the 19th century, from the electric light to the telegraph, steam engine, Fréjus Rail Tunnel, and Suez Canal. As such it foreshadows the Futurism movement. In the first nine months, it was staged 100 times in Italy and abroad. It is still performed and was recently (2002) staged in Milan.