A mandala (Sanskrit: मण्डल, romanized: maṇḍala, lit. 'circle', [ˈmɐɳɖɐlɐ]) is a geometric configuration of symbols. In various spiritual traditions, mandalas may be employed for focusing attention of practitioners and adepts, as a spiritual guidance tool, for establishing a sacred space and as an aid to meditation and trance induction. In the Eastern religions of Hinduism, Buddhism, Jainism and Shinto it is used as a map representing deities, or especially in the case of Shinto, paradises, kami or actual shrines.

In Hinduism, a basic mandala, also called a yantra, takes the form of a square with four gates containing a circle with a centre point. Each gate is in the general shape of a T. Mandalas often have radial balance.

A yantra is similar to a mandala, usually smaller and using a more limited colour palette. It may be a two- or three-dimensional geometric composition used in sadhanas, puja or meditative rituals, and may incorporate a mantra into its design. It is considered to represent the abode of the deity. Each yantra is unique and calls the deity into the presence of the practitioner through the elaborate symbolic geometric designs. According to one scholar, "Yantras function as revelatory symbols of cosmic truths and as instructional charts of the spiritual aspect of human experience"

Many situate yantras as central focus points for Hindu tantric practice. Yantras are not representations, but are lived, experiential, nondual realities. As Khanna describes:

Despite its cosmic meanings a yantra is a reality lived. Because of the relationship that exists in the Tantras between the outer world (the macrocosm) and man's inner world (the microcosm), every symbol in a yantra is ambivalently resonant in inner–outer synthesis, and is associated with the subtle body and aspects of human consciousness.

The term 'mandala' appears in the Rigveda as the name of the sections of the work, and Vedic rituals use mandalas such as the Navagraha mandala to this day.

For each tantric tradition, its mandala is the most important visual form. Abhinavagupta in his Tantrāloka textually describes the four key mandalas of the Trika tradition, which were translated, decoded and illustrated by Christian de Vietri in his book Trika Maṇḍala Prakāśa.

In Vajrayana Buddhism, mandalas have been developed also into sandpainting. They are also a key part of Anuttarayoga Tantra meditation practices.