Sheikh Karimul Makhdum Day is observed in the Philippines every November 7 and is recognized as a special working holiday. This day commemorates the introduction of Islam to the Philippines and the establishment of the country's first mosque, the Sheikh Karimul Makhdum Mosque, which was founded by the Arab merchant and Sufi sheikh Karimul Makhdum in 1380 on Simunul Island. Although the original mosque has not survived, its architecture is believed to have reflected the indigenous Moro style. The holiday was first designated in 1991 in the Autonomous Region in Muslim Mindanao and continued after its transition to the Bangsamoro Autonomous Region in Muslim Mindanao in 2019. In July 2025, President Bongbong Marcos declared it a national holiday. The observance highlights the historical significance of Islam in the Philippines, where the Muslim population is estimated to be between 6% and 11%, primarily residing in the Bangsamoro region.