Sindoor (Hindi-Urdu: सिन्दूर or سندور) is a traditional red or orange-red colored cosmetic powder from India, usually worn by married women along the parting of their hair. Usage of sindoor denotes that a woman is married in many Hindu communities, and ceasing to wear it usually implies widowhood. The main component of traditional sindoor is usually vermilion.

Sindoor is traditionally applied at the beginning or completely along the parting-line of a woman’s hair (also called maang) or as a dot on the forehead. Sindoor is the mark of a married woman in Hinduism. Single women wear the dot in different colors ("bindi" in Hindi) but do not apply sindoor in their maang. Hindu widows do not wear the sindoor, signifying that their husband is no longer alive. A version used in Hindu rituals or puja is known as Kumkum. This also lends itself to the name of a wedding ritual in some Hindu communities, known as 'Haldi-Kumkum'. The sindoor is first applied to the woman by her husband on the day of her wedding and is called as Sindoor Dana ceremony. After this time she must apply this every day herself in the parting of her hairline.