Alauddin al-Kahar

Alauddin Ri'ayat Syah al-Kahar
Grave of al-Kahar in Baitur Rijal (Kandang XII), Banda Aceh
Sultan of Aceh Sultanate
Reign	1537/1539 – 28 September 1571
Predecessor	Salahuddin of Aceh
Successor	Ali Ri'ayat Syah I
Born	unknown Banda Aceh, Aceh Sultanate (now Indonesia)
Died	(1571-09-28)28 September 1571 Banda Aceh, Aceh Sultanate, (now Indonesia)
Burial	Cemetery Complex of the Sultans of Aceh Kandang XII, Banda Aceh
Spouse	unknown
Issue	Abdullah Husain Sri Alam Abdul Jalil
Father	Ali Mughayat Syah
Mother	unnamed daughter of Inayat Syah

Alauddin Ri'ayat Syah al-Kahar (died 29 September 1571) was the third Sultan of the Aceh Sultanate, reigning from either 1537 or 1539 until his death. He is considered to be one of the strongest rulers in the history of the sultanate and greatly strengthened Aceh. Alauddin's reign was marked by increased conflict with his Portuguese and Malay rivals and his dispatching of envoys to the Ottoman sultan, Suleiman the Magnificent in the 1560s.