In Hindu theology, Gandharvas act as messengers between the gods and humans. In Hindu law, a Gandharva marriage is one contracted by mutual consent and without formal rituals.
Gandharvas are mentioned extensively in the epic Mahabharata as associated with the Devas (as dancers and singers) and with the Yakshas, as formidable warriors. They are mentioned as spread across various territories.
Gandharvas can fly through the air, and are known for their skill as musicians. They are connected with trees and flowers, and are described as dwelling in the scents of bark, sap, and blossom. They are among the beings of the wilderness that might disturb a monk meditating alone.
Among the notable gandharvas are mentioned (in DN.20 and DN.32) Panāda, Opamañña, , Cittasena, Rājā. Janesabha is probably the same as Janavasabha, a rebirth of King Bimbisāra of Magadha. Mātali the Gandharva is the charioteer for Śakra.
Timbarū was a chieftain of the gandharvas. There is a romantic story told about the love between his daughter Bhaddā Suriyavaccasā (Sanskrit: Bhadrā Sūryavarcasā) and another gandharva, Pañcasikha (Sanskrit: Pañcaśikha). Pañcasikha fell in love with Suriyavaccasā when he saw her dancing before Śakra, but she was then in love with Sikhandī (or Sikhaddi), son of Mātali the charioteer. Pañcasikha then went to Timbarū's home and played a melody on his lute of beluva-wood, on which he had great skill, and sang a love-song in which he interwove themes about the Buddha and his Arhats.
Later, Śakra prevailed upon Pañcasikha to intercede with the Buddha so that Śakra might have an audience with him. As a reward for Pañcasikha's services, Śakra was able to get Suriyavaccasā, already pleased with Pañcasikha's display of skill and devotion, to agree to marry Pañcasikha.
Pañcasikha also acts as a messenger for the Four Heavenly Kings, conveying news from them to Mātali, the latter representing Śakra and the devas.
Gandharva or gandhabba is also used in a completely different sense, referring to a being (or, strictly speaking, part of the causal continuum of consciousness) in a liminal state between birth and death.