Marthad'ilan Yu'nim (Arabic: àñëï ãÃÂàÃÂÃÂùà) also known as Marthad al-Khayr, was a Himyarite king who primarily reigned in the late 5th century CE. He is known for his involvement in the Basus War.
As attested in inscriptions, his name is Marthad'ilan Yu'nim; his full name being Marthad ibn Lakhni'ah Yanuf al-Himyari. In the books of Arab heritage, his name is Marthad al-Khayr ibn Dhi Jadan. The word Yun'im is Himyaritic for "blessed" which is al-Khayr in Arabic.
Marthad'ilan Yu'nim started his reign in the year 480. According to the inscription YM 1200, he constructed a synagogue and repaired an unknown monotheistic place of worship known as a Kenesit. Christian J. Robin believed his reign ended in the year 485 CE however there is an inscription dated to 502 CE which does mention his name along with his siblings; the inscription also does not mention him with royal titles. According to the Arabian traditions, Marthad'ilan Yu'nim was succeeded by a king named Qarmal.
Marthad'ilan Yu'nim sent a force of five hundred soldiers to assist Imru' al-Qays in his mission to reunite the Taghlib and Banu Bakr tribes in the Basus War in order to defeat the Banu Asad.