The third eye (also known as the inner eye) is a mystical and esoteric concept referring in part to the ajna (brow) chakra in certain Eastern and Western spiritual traditions. It is also spoken of as the gate that leads within to inner realms and spaces of higher consciousness. In New Age spirituality, the third eye may alternately symbolize a state of enlightenment or the evocation of mental images having deeply-personal spiritual or psychological significance. The third eye is often associated with visions, clairvoyance, precognition, and out-of-body experiences, and people who have allegedly developed the capacity to use their third eyes are sometimes known as seers.

In Hinduism and Buddhism, the third eye is a symbol of enlightenment (see moksha and nirvana). In the Indian tradition, it is referred to as the jjanacaksu, the eye of knowledge, which is the seat of the 'teacher inside' or antar-guru. The third eye is the ajna chakra (sixth chakra) also known as brow chakra or brow centre. This is commonly denoted in Indian and East Asian iconography with a dot, eye or mark on the forehead of deities or enlightened beings, such as Shiva, the Buddha, or any number of yogis, sages and bodhisattvas. This symbol is called the "Third Eye" or "Eye of Wisdom", or, in Buddhism, the urna. In Hinduism, it is believed that the opening of Shiva's third eye causes the eventual destruction of the universe.

Many Hindus wear a tilak between the eyebrows to represent the third eye.

In the Upanishads, a human being is likened to a city with ten gates. Nine gates (eyes, nostrils, ears, mouth, urethra, anus) lead outside to the sensory world. The third eye is the tenth gate and leads to inner realms housing myriad spaces of consciousness.