Portrait of Juan Montalvo surrounded by the country name (above) and his name (below). Coat of arms on the right.

Juan María Montalvo Fiallos (1832–1889) was an Ecuadorian author and essayist.

He held diplomatic posts in Italy and France from 1857 to 1859. A political liberal, Montalvo's beliefs were marked by anti-clericalism and a keen hatred for the two caudillos that ruled Ecuador during his life: Gabriel García Moreno and Ignacio de Veintemilla. After an issue of El Cosmopolita viciously attacked Moreno, Montalvo was exiled to Colombia for seven years.

In the late seventies Juan Montalvo was twice exiled to France, remaining there from 1879, as punishment for Las catilinarias (1880), the work that made him famous throughout intellectual circles in the United States, Europe and the rest of Latin America. Alongside full-length books, Montalvo was an accomplished essayist, and his Siete Tratados (1882) and Geometría Moral (published in 1902, after his death) were popular in Ecuador and were banned by Veintemilla. He also wrote a witty sequel to Miguel de Cervantes's Don Quixote, called Capítulos que se le Olvidaron a Cervantes ("Chapters Cervantes Forgot"), published posthumously in 1895.

Denomination in digits and in words, year of issue, name of the Central Bank of Ecuador above.