Raja (; from IAST rājan-) is a noble or royal Sanskrit title historically used by some Indian rulers and monarchs and highest-ranking nobles. The title was historically used in the Indian subcontinent and Southeast Asia.

The title has a long history in South Asia and Southeast Asia, being attested from the Rigveda, where a rājan- is a ruler, see for example the daśarājñá yuddhá, the "Battle of Ten Kings".

The title has equivalent cognates in other Indo-European languages, notably the Latin Rex and the Celtic Rix.

The Maratha title "Rao" (or "Rao") functions as both a given name and an honorific title, derived from words like the Sanskrit "Rājā" meaning "king," is a associated with the Kshatriya varna and can be considered a Kshatriya title.

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