The flag of São Tomé and Príncipe consists of three horizontal stripes and a red isosceles triangle. The aspect ratio of the flag is 1:2.

Colors and their HEX codes:

1. Green (#12AD2B): top stripe, occupies 1/3 of the flag's height.
2. Yellow (#FFCD00): middle stripe, occupies 1/3 of the flag's height.
3. Black (#000000): bottom stripe, occupies 1/3 of the flag's height.
4. Red (#D21034): triangle, based on the flag's hoist side, extending to half the flag's length.

Two five-pointed stars are placed in the yellow stripe, one on each side of the triangle. The stars are black (#000000) and measure 1/5 of the flag's height. They are separated by an invisible vertical line that divides the flag's length into two equal parts.