The flag of Rotterdam, the Netherlands, was adopted 10 February 1949. It is a horizontal triband of green-white-green. This color combination is also found in the coat of arms of Rotterdam. The ratio is 2:3.
The colors green and white are the colors of Rotterdam since the Middle Ages, but the employment of the flag of Rotterdam has varied greatly. The green refers to the Court of Wena and the white symbolizes the Rotte.