Giay men wear trousers, short vest and wind a turban around their heads. Women wear a five-paneled vest open at the side and buttoning under the right armpit and trousers. They wear their hair wound round the head or wind with a turban. Decorated motifs are often seen on women wear, linen sacks, pillows, curtains and children's clothes.

The Giay villages are very crowded, some may contain hundreds of households. The Giay people in Ha Giang and Cao Bang often live in houses on stilts and those who are in Lao Cai and Lai Chau live in houses built level with the ground. The central bay of the house serves for receiving guests and for placing ancestor altar. Each couple lives in a small room of other bays. Another bay serves as a kitchen.

Patriarchal custom is the rule of Giay families. The children take the family name of the father. The family of the young roan seeks marriage for their son. After the wedding, the bride comes to live with her husband's family. However matriloc ate is also popular. In the past, marriage by "kidnapping" was occured when the young man and women were engaged but the male family could not afford direct betrothal and wedding ceremonies. The man had to kidnap his woman.

Giay women in pregnancy must obey taboos and an altar has been set up for the delivery. When the baby is a month old, a ceremony is held to inform the ancestors of the birth and pray for their protection. At the ceremony the ofliciant writes on red cloth the horoscope of the baby with the hour, day, month and year of birth. The horoscope is consulted for "age concordance" when the day comes for the baby, now grown up, to choose a spouse, and to determine the hour of his or her burial.

According to Giay's cosmogonies concepts, the universe is composed of three levels. Apart from the middle one where human beings are living, there are the upper one and the underground. When a person dies it is customary that if funeral and burial are carefully organized the deceased will be carried to the heaven. On the contrary, it will be doomed to the underground.

On the altar, the Giay worship not only their ancestors but also the genies of the heaven, the earth and the kitchen. They also worship the Goddess of childbirth and even the ancestors of the wife. The ancient ancestors are worshipped as the guardian genies.

The cultural heritage of the Giay is rich including many ancient tales, poems, proverbs, puzzles and alternating songs. Many stories explain natural phenomena. Some stories are narrated in accompaniance with songs (sung stories). Folksongs are popular with various genres and rhythms, particularly love duet sentences are very attractive entertainment.