The name of Qabus ibn al-Mundhir, who had succeeded his slain brother 'Amr III ibn al-Mundhir as Lakhmid king in 569, is an Arabic form of the Persian name "Kavus", adopted under the influence of his Sassanid Persian overlords.

Not much is known of his reign except that he suffers a heavy defeat at the hands of the rival Constantinople-sponsored Ghassanid tribe under Al-Mundhir III ibn al-Harith in 570.