Ao Dai is a traditional garment of Vietnam which is worn mostly in big occasions, at school or at work. It has a long history of development since the 18th century. After being evolved from the outfit of officers under the Nguyen Empire into the five-paneled aristocratic gowns, it continue to be innovative into a two pieces dress to catch the modern trend in the 1920s and 1930s. At that time it had a large form which covered the entire body; however, in the 1950s, some designers in Saigon tightened it to fit to the curves. That version is considered as the national costume which is widely wear by Vietnamese women nowadays. The fabric of Ao Dai is also diverse in choices. The basic material is linen and cotton, which is usually worn by students in high schools and universities. At bigger occasions, people wear Ao Dai made from high quality silk and velvet, and they can add more decorations such as light metal flowers or embroidered patterns. For the upper class people, they like to wear brocade fabric with turban and other accessories such as gold necklace and bracelet. Ao Dai is extremely popular in the South of Vietnam, and we can easily come across people wearing it everywhere on the streets. It emphasizes the feminine beauty and the reticence of the East Asian people. Vietnamese people are very proud of it since it is only one of the few Vietnamese words that appear in the national dictionaries. We even host many competitions that relating to Ao Dai such as Miss Ao Dai and other competitions for designers to honor its importance. Ao Dai is a remarkable value of Vietnamese tradition, and we will always preserve and develop it.