Flag of Monaco

The national flag of Monaco consists of two equal horizontal bands of red and white. Red occupies the top half of the field, while the bottom half is entirely white. This rectangular design is defined by a specific aspect ratio of four units high by five units wide.

The red and white colors represent the traditional heraldic tinctures of the House of Grimaldi, the dynasty that has governed the territory since 1297. These specific hues are taken directly from the lozengy, or diamond-shaped, patterns found on the family's historic shield. By utilizing these colors, the flag serves as a visual link to the principality's medieval origins and its continuity under a single ruling family. No additional emblems are included on the national flag, focusing the symbolism entirely on these ancestral dynastic colors.

Prince Charles III officially adopted the current bicolor design on April 4, 1881. Before this standardization, the principality frequently used a white flag featuring the full Grimaldi coat of arms. The 1881 decree simplified the national colors into the current horizontal format to serve as a distinct civil ensign. While it shares a color scheme with the flag of Indonesia, Monaco's version was established significantly earlier and utilizes different dimensional proportions.