The Flag of Transvaal (Vierkleur Flag) was the flag of the former Transvaal province of South Africa.

It was previously the flag of the historic Transvaal Republic, officially called the Zuid Afrikaanse Republiek or in English translation, the South African Republic, from 1857 to 1874, 1875-1877, and 1881-1902.

The Vierkleur Flag features three horizontal stripes of red, white, and blue (recalling the Dutch national flag), with a vertical green stripe at the hoist, and is known as the Vierkleur (lit. four colours). The former national flag of South Africa (from 1928—1994) had, as part of a feature contained within its central white bar, a horizontal flag of the Transvaal Republic. Wikipedia