Tissa, later Devanampiya Tissa (Sinhala: දේවානම්පිය තිස්ස, lit. 'Loved by Gods', [ˈdeːʋaːnampijə t̪issə]), also known as Devanape Tis (Sinhala: දෙවනපෑ තිස්, [ˈdeʋənəpǣ t̪is]), was one of the earliest kings of Sri Lanka based at the ancient capital of Anuradhapura. According to the traditional chronology, he ruled from 307 BC to 267 BC, but the modified chronology adopted by modern scholars such as Wilhelm Geiger assigns his reign to 247 BC to 207 BC.His reign was notable for the arrival of Buddhism in Sri Lanka under the aegis of the Mauryan Emperor Ashoka the Great. The primary source for his reign is the Mahavamsa, which in turn is based on the more ancient Dipavamsa.

Tissa was the second son of Mutasiva of Anuradhapura. The Mahavamsa describes him as being "foremost among all his brothers in virtue and intelligence".

The Mahavamsa mentions an early friendship with Ashoka. Chapter IX of the chronicle mentions that "the two monarchs, Devanampiyatissa and Dharmasoka, already had been friends a long time, though they had never seen each other", Dharmasoka being an alternate name for Ashoka. The chronicle also mentions Tissa sending gifts to the mighty emperor of the Maurya; in reply, Ashoka sent not only gifts but also the news that he had converted to Buddhism, and a plea to Tissa to adopt the faith as well. The king does not appear to have done this at the time, instead adopting the name Devānaṃpiya "Beloved of the Gods" and having himself consecrated King of Lanka in a lavish celebration.

Devanampiyatissa is traditionally said to have been succeeded by his younger brothers Uttiya and Mahasiva. His other brother Mahanaga, Prince of Ruhuna was the founder of the Principality of Ruhuna.

In 306 BC, King Devanampiya Tissa was coronated at the Royal Mandapa for the second time at the request of Emperor Ashoka.

Emperor Ashoka took an interest in the propagation of Buddhism across the known world. According to Sri Lankan tradition, it was decided that his son, Mahinda, would travel to Sri Lanka and attempt to convert the people there. The events surrounding Mahinda's arrival and meeting with the king form one of the most important legends of Sri Lankan history.

According to the Mahavamsa King Devanampiyatissa was out enjoying a hunt with some 40,000 of his soldiers near a mountain called Mihintale. The date for this is traditionally associated with the full moon day of the month of Poson.

Having come to the foot of Missaka, Devanampiyatissa chased a stag into the thicket, and came across Mahinda (referred to with the honorific title Thera); the Mahavamsa has the great king 'terrified' and convinced that the Thera was in fact a 'yakka', or demon. However, Thera Mahinda declared that 'Recluses we are, O great King, disciples of the King of Dhamma (Buddha) Out of compassion for you alone have we come here from Jambudipa'. Devanampiyatissa recalled the news from his friend Ashoka and realised that these are missionaries sent from India. Mahinda wanted to test the intelligence of the king so he asked him these questions: