The twin explosions happened after a mass at 8am (local time). The victims were mostly government troops and civilians. No one has immediately claimed responsibility for the attacks.
Secretary of National Defence of the Philippines Delfin Lorenzana strongly protested the attacks, saying that he has directed the army stay alert and ensure security in religious establishments and public areas to prevent attack risks.
The bombings took place days after the ratification of the Bangsamoro Organic Law (BOL), a new law that paves the way for the creation of a wider autonomous region for Muslim Filipinos in Mindanao.
Although Muslims overwhelmingly approved the law, Sulu province, where Jolo is located, voted against the autonomous government.
The Commission on Elections earlier said the law was ratified after getting more than 1.5 million favourable votes.