Raja Dahir Sen, or simply Raja Dahir (Sindhi: راجا ڏاھر‎; Sanskrit: राजा दाहिर, IAST: Rājā Dāhir; 663 – 712 AD) was the last Hindu ruler of Sindh. He presided over the Pushkarna Brahmin Dynasty of Sindh, which included territories that now constitute parts of the modern-day states of Afghanistan, the Balochistan region of Iran and Pakistan, and parts of Punjab. In 711 AD, his kingdom was conquered by Muhammad bin Qasim, an Arab general, for the Umayyad Caliphate. He was killed at the Battle of Aror at the banks of the Indus River, near modern-day Nawabshah.

The Chach Nama is the oldest chronicles of the Arab conquest of Sindh. It was translated in Persian by Muhammad Ali bin Hamid bin Abu Bakr Kufi in 1216 CE from an earlier Arabic text believed to have been written by the Thaqafi family (relatives of Muhammad bin Qasim).

Dahir's kingdom was invaded by Ramal at Kannauj. After initial loss, the enemy advanced on Aror and he allied himself with Alafi, an Arab. Alafi and his warriors (who were exiled from the Umayyad caliph) were recruited; they led Dahir's armies in repelling the invading forces, remaining as valued members of Dahir's court. In are later war with the caliphate, however, Alafi served as a military advisor but refused to take an active part in the campaign; as a result, he later obtained a pardon from the caliph.

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