There are six orders of belts: white, yellow, green, blue, red, and black. The colours have not been arbitrarily chosen. They are, in fact, steeped in tradition. The colours of black, red, and blue denoted the various levels of hierarchy during the Koguryo and Silla Dynasties.

White Signifies innocence, as that of a beginning student who has no previous knowledge of Taekwon-Do.
Yellow Stripes
Yellow Signifies the Earth from which a plant sprouts and takes root as the Taekwon-Do foundation is being laid.
Green Stripes
Green Signifies the plant's growth as the Taekwon-Do skill begins to develop.
Blue Stripes
Blue Signifies the Heaven, towards which the plant matures into a towering tree as training in Taekwon-Do progresses.
Red Stripes
Red Signifies danger, cautioning the student to exercise control and warning the opponent to stay away.
Black Stripes
Black Opposite of white, therefore, signifying the maturity and proficiency in Taekwon-Do. It also indicates the wearer's imperviousness to darkness and fear.