Sitangkai is a coastal municipality in the island province of Tawi-Tawi.

The municipality has a land area of 735.46 square kilometers or 283.96 square miles which constitutes 20.28% of Tawi-Tawi’s total area. Its population as determined by the 2020 Census was 37,319. This represented 8.48% of the total population of Tawi-Tawi province, or 0.85% of the overall population of the Bangsamoro Autonomous Region in Muslim Mindanao. Based on these figures, the population density is computed at 51 inhabitants per square kilometer or 131 inhabitants per square mile.