The attacks began with the detonation of an explosive device attached to a bus carrying students from Sardar Bahadur Khan Women's University. The blast completely destroyed the vehicle, killing 14 women and injuring 19 others. A short time later, a suicide bomber struck at the nearby Bolan Medical Complex, where victims of the initial bombing were being treated. A team of five gunmen then forced its way into the compound, as senior Quetta political officials were visiting the injured, sparking an hours-long shootout with security forces. The siege ended with at least 12 casualties, including four attackers, four Pakistan Army soldiers and four hospital nurses. One of the gunmen survived the assault and was captured by government forces.
It is believed that the intended targets of the bus bombing were Shia from the Hazara ethnic minority, who have been the targets of previous sectarian attacks in Balochistan. However, due to an earlier change of route, the bus carried a more ethnically mixed group and has been described as "the wrong target" of the perpetrators.