The ao dai is the native Vietnamese dress. It is similar to the Chinese cheongsam as it is long and fitted with slits on the sides worn over pantaloon and it is basically used by Vietnamese women. Tight-fitting bodice with slits on the side, it is a fusion of modern and conservative culture of Vietnam. But the current ao dai has its share of evolution due to the history of Vietnam and its preference for being traditional and conservative.

Before the ao dai was introduced, the women characteristically wore a halter top (ao yem) and a skirt (vay). But as their culture was influenced by the Chinese who favors conventional and less revealing types of clothes, it was ordered by Lord Nguyen Phuc Khoat of Hue in 1744 that members of his court, both men and women should wear a gown with buttons down the front paired with trousers. It serves as a distinguishing trait between the courtiers in Hanoi of the Trinh Lords, who wore a long skirt and side-split jacket.

The ao dai was derived from the ao ngu than. It had two flaps, both sewn together at the front and back with a small flap which was hidden under the main flap in the front. The gown seemed to look as if it had two flaps with slits on both sides. This is an attribute of the Vietnamese traditional costume we know today. But the ao ngu than had much larger flaps and was fitted loosely over the body. It is also button-down as well as a high-collared feature to it much like what we can picture the dress today. Sometimes, the yem or the halter top could be glimpsed underneath when women would wear it with the top buttons undone.

Artist Cat Tuong of Hanoi conceived a design derived from the ao ngu than combined with the Parisian fashions in 1930. It is floor-length and body-fitted by using darts. It also featured a nipped-in waist. As the materials of cloth and fabric were becoming expensive, the multi-layered flaps were replaced with wider panels, which discarded the need to sew the panels jointly. The stylish and revamped traditional costume hit popularity status when it was featured in January of 1935 in a newspaper named Today and was promoted by the artist group Tu Luc van doan to serve as modern-day national costume. But the stylish and western-influenced costume was phased-out temporarily with the waging of World War II.

The ao dai has many versions evolved throughout the years. There were collarless versions made famous by former first lady of South Vietnam Madame Nhu in 1958. There is also a mini made for everyday use, its panels were knee-length and slits up to the waist. But whatever the design, it remains to be a beautiful costume revealing the strong yet feminine side of Vietnamese women.