The poem describes the royal birth of Rāma (Rama) in the kingdom of Ayodhyā (Oudh), his tutelage under the sage Viśvāmitra, and his success in bending Śiva (Shiva)'s (Shiva's) mighty bow at the bridegroom tournament of Sītā, the daughter of King Janaka, thus winning her for his wife. After Rāma is banished from his position as heir by an intrigue, he retreats to the forest with his wife and his favourite half brother, Lakṣmaṇa, to spend 14 years in exile. There Rāvaṇa, the demon-king of Laṅkā, carries off Sītā to his capital, while her two protectors are busy pursuing a golden deer sent to the forest to mislead them. Sītā resolutely rejects Rāvaṇa's attentions, and Rāma and his brother set about to rescue her. After numerous adventures they enter into alliance with Sugrīva, king of the monkeys; and with the assistance of the monkey-general Hanumān and Rāvaṇa's own brother, Vibhīṣana, they attack Laṅkā. Rāma slays Rāvaṇa and rescues Sītā, who in a later version undergoes an ordeal by fire in order to clear herself of the suspicions of infidelity. When they return to Ayodhyā, however, Rāma learns that the people still question the queen's chastity, and he banishes her to the forest. There she meets the sage Vālmīki (the reputed author of the Rāmāyaṇa) and at his hermitage gives birth to Rāma's two sons. The family is reunited when the sons become of age, but Sītā, after again protesting her innocence, asks to be received by the earth, which swallows her up.

The poem enjoys immense popularity in India, where its recitation is considered an act of great merit. Many of its translations into the vernacular languages are themselves works of great literary merit, including the Tamil version of Kampaṉ, the Bengali version of Kṛttibās, and the Hindi version, Rāmcaritmānas, of Tulsīdās. Throughout North India the events of the poem are enacted in an annual pageant, the Rām Līlā, and in South India the two epics, the Rāmāyaṇa and the Mahābhārata, even today make up the story repertoire of the kathākali dance-drama of Malabar. The Rāmāyaṇa was popular even during the Mughal period (16th century), and it was a favourite subject of Rājasthānī and Pahārī painters of the 17th and 18th centuries.

The story also spread in various forms throughout Southeast Asia (especially Cambodia, Indonesia, and Thailand); and its heroes, together with the Pāṇḍava brothers of the Mahābhārata, were the heroes of traditional Javanese-Balinese theatre, dance, and shadow plays. Incidents from the Rāmāyaṇa are carved in bas-relief on many Indonesian monuments—for example, at Panataran in eastern Java.