Prior to the Arab Spring War in 2011, the national flag of Libya used to have only one color; green. More specifically, it consisted of a simple green field with no other characteristics.
Also, many signal flags are just one color. Then, of course, the flag of surrender is but one color; white.
Currently, there is no national flag with only one color.
Lybia has a green flag
Libya has only green colour on her flag.
The Libya flag is the only country to have a flag with only one color. The flag is solid green. It is green because green is the national color of libya showing their devotion to islam.
Libya
Prior to the Arab Spring War in 2011, the national flag of Libya used to have only one color; green. More specifically, it consisted of a simple green field with no other characteristics. Currently, there is no national flag with only one color.
There is no country that has a national flag with color black and white only. However, there some that contains black and white as part of the colors. Such countries include South Korea, Kenya, Swaziland and many others.
Turkey, Switzerland, Poland, Monaco, Canada, and Indonesia. The constituent country of Northern Ireland's flag also only contains white and red.
Nepal is the only Asian country without a rectangular flag. Instead, it's flag is in the shape of two overlapping triangles.
Nepal is the only country with a flag that is not a rectangle
Mozambique.
libya,africa. The color is nothing but green
Brazil