Pardah or purdah (from Hindi-Urdu پردہ, पर्दा, meaning "curtain") is a religious and social practice of female seclusion prevalent among some Muslim and Hindu communities. It takes two forms: physical segregation of the sexes and the requirement that women cover their bodies so as to cover their skin and conceal their form. A woman who practices purdah can be referred to as pardanashin or purdahnishan. The term purdah is sometimes applied to similar practices in other parts of the world.

Practices that restricted women's mobility and behavior existed among all religious groups since ancient times and intensified with the arrival of Islam. By the 19th century, purdah became customary among Hindu elites. Purdah was not traditionally observed by lower-class women.

Physical segregation within buildings is achieved with judicious use of walls, curtains, and screens. A woman's withdrawal into purdah usually restricts her personal, social and economic activities outside her home. The usual purdah garment worn is a burqa, which may or may not include a yashmak, a veil to conceal the face. The eyes may or may not be exposed.

Married Hindu women in parts of Northern India observe purdah, with some women wearing a ghoonghat in the presence of older male relations on their husbands' side; Muslim women observe purdah through the wearing of a burqa.

Purdah was rigorously observed under the Taliban in Afghanistan, where women had to observe complete purdah at all times when they were in public. Only close male family members and other women were allowed to see them out of purdah. In other societies, purdah is often only practised during certain times of religious significance.