Srivijaya (also written Sri Vijaya, Indonesian/Malay: Sriwijaya, Thai: ศรีวิชัย rtgs: Siwichai, Sanskrit: श्रीविजय, Śrīvijaya, known by the Chinese as Shih-li-fo-shih and San-fo-ch'i) was a dominant thalassocratic city-state based on the island of Sumatra, Indonesia, which influenced much of Southeast Asia. Srivijaya was an important centre for the expansion of Buddhism from the 8th to the 12th century. In Sanskrit, śrī means "fortunate", "prosperous", or "happy" and vijaya means "victorious" or "excellence".

The earliest evidence of its existence dates from the 7th century. A Tang Chinese monk, Yijing, wrote that he visited Srivijaya in 671 CE for 6 months. The earliest known inscription in which the name Srivijaya appears also dates from the 7th century in the Kedukan Bukit inscription found near Palembang, Sumatra, dated 16 June 682 CE. Between the late 7th and early 11th century, Srivijaya rose to become a hegemon in Southeast Asia. It was involved in close interactions — often rivalries — with the neighbouring Medang Kingdom, Khmer Empire and Champa. Srivijaya's main foreign interest was nurturing lucrative trade agreements with China which lasted from the Tang dynasty to the Song dynasty. Srivijaya had religious, cultural and trade links with the Buddhist Pala Empire of Bengal, as well as with the Islamic Caliphate in the Middle East. The kingdom ceased to exist in the 13th century due to various factors, including the expansion of the Javanese, Singhasari, and Majapahit empires.