The flag of Lombardy is one of the official symbols of the region of Lombardy, Italy. The current flag was officially adopted on 4 February 2019 although it was de facto used since 12 June 1975. The flag is a field of green, representing the Po Valley, with the Rosa Camuna (a symbol of the region derived from a prehistoric drawing made by the ancient Camuni) in white in the centre, representing the light.

The modern version of the Rosa Camuna was designed by Bruno Munari, Bob Noorda, Roberto Sambonet and Pino Tovaglia in 1975, and became the regional coat of arms on 12 June 1975. After that, a 2:3 version of the Rosa Camuna was used like a provisional flag. Since 1990, the Lega Nord party tried to establish the Saint Ambrose's flag (a red cross on a white field), used by the city of Milan and the Lombard League during the Middle Ages, without succeeding. In 2007 a study commissioned by the Region concluded that the most representative flag was the one of the Duchy of Milan (the so-called Ducale, composed by quartering the Biscione and the Reichsadler), but the proposal was never discussed.

The idea of combining the Rosa Camuna with Saint Ambrose's Cross first appeared in 2011: six sketches were published and polled on the daily newspaper Corriere della Sera, without sequel. A new proposal was discussed in 2015, but it was also rejected. The provisional flag was finally adopted with a unanimous vote of the Regional Council on 29 January 2019, becoming official on 4 February 2019.