The Trāyastriṃśa heaven is an important world of the devas in the Buddhist cosmology. The word trāyastriṃśa is an adjective formed from the numeral trayastriṃśat, "33" and can be translated in English as "belonging to the thirty-three [devas]". It is primarily the name of the second in the six heavens of the desire realm in Buddhist cosmology, and secondarily used of the devas who dwell there. Trāyastriṃśa is ruled by Śakra, also known as Indra.

A Deva in Buddhism is a type of celestial being or god who shares the god-like characteristics of being more powerful, longer-lived, and, in general, much happier than humans, although the same level of veneration is not paid to them as to Buddhas.