The regional flag of São Paulo, Brazil, adopted officially on 3 September 1948. The flag is made of wool bunting with a cotton hoist and is machine stitched. There is a thin cord halyard in the hoist which is made by turning over the edge of the flag. The design consists of 13 black and white horizontal stripes. The canton is red with four five-pointed yellow felt stars surrounding a white disc bearing a dark blue felt map of Brazil.

The flag was designed in 1888 by Júlio Ribeiro as a republican flag for Brazil, the red, white and black colours were intended to represent the three races - African, European and Native American that made up the county's population. The flag originally had 15 stripes. Between 1888 and 1948 it was used as an unofficial state flag and symbol of the Constitutionalist movement.