Chandrabhanu (died 1263) or Chandrabhanu Sridhamaraja is the King of Tambralinga Kingdom in present day Thailand.
A Javaka (Srivijayan), he is known to have ruled from during the period of 1230 until 1263.
He is also known for building a well-known Buddhist stupa in southern Thailand.
He spends more than 30 years in his attempt to conquer Sri Lanka.
He is eventually defeated by the forces of the Pandyan Dynasty from Tamilakkam continent (present day South India in 1263 and is killed by the brother of the south Indian Emperor Jatavarman Sundara Pandyan.
In 1247, he sends an expedition to the island, ostensibly to acquire the Buddhist relic from the island.
His forces, using poison darts, are able to occupy the Jaffna kingdom, the northern part of the island in 1255.
Repeated attempts to conquer the rest of the island ensue.
In 1258, his forces face an invasion of the island by the forces of the Pandyan Dynasty, commanded by Jatavarman Sundara Pandyan I, and Chandrabhanu submits to Pandyan rule, bringing the Jaffna kingdom under Pandyan suzerainty.
From 1262-1264, Tambralinga forces, using Chola and Pandyan soldiers commanded by Chandrabhanu's son Savakanmaindan and two Sinhalese princes, are defeated by the Pandyans, led in the invasion by Jatavarman Vira Pandyan I.
In 1270, Savakanmaindan, retained on the Jaffna throne under Pandyan suzerainty, attemptsto invade the south of the island once again, only to be defeated decisively by the Pandyans under Maravarman Kulasekara Pandyan I by the late 1270s.
The defeat is so complete that in 1290, Tambralinga is absorbed by the neighboring Thai Kingdoms.