Abhayagiri Vihara, founded during the reign of King Walagamba, became a prominent educational centre that nurtured the Mahayana tradition until the Chola invasion during the Polonnaruwa period. This research explores the curriculum of Abhayagiri Vihara, using content analysis of relevant literary sources. The findings indicate that Abhayagiri was a well-structured educational institution where local and foreign Bhikkhus, Bhikkhunis, and laypeople studied. The curriculum comprised formal, informal, and nonformal education. Formal education covered languages, poetry, religion, technology, art, history, medicine, and Gupta Vidya. Nonformal education involved practical skills like creating gold items, producing coins and tiles, and writing poetry. Assemblies and meetings were organized to encourage knowledge sharing. The Sannipatasala, a major hall in the Vihara, was used for large gatherings. Other co-curricular activities included the Perahara processions and religious worship. Abhayagiri also engaged in welfare activities, as seen in the Pinkama event, where water tanks were offered, reflecting a broader commitment to community service. The maintenance of the temple was part of a hidden curriculum that emphasized discipline, honesty, and respect. Bribery, corruption, and immoral behavior were strictly forbidden, and punishment for offenders served as a deterrent. Respect for elders and following monastic hierarchy were key aspects of informal education. The curriculum at Abhayagiri Vihara balanced academic knowledge and moral development, offering valuable lessons for modern educational systems in Sri Lanka by promoting holistic development and ethical behavior among students.