Kutubdia (Bengali: কুতুবদিয়া) is an upazila of Cox's Bazar District[5] in the Division of Chittagong, Bangladesh.

The upazila consists of an island in the Bay of Bengal, off the coast near Chakaria, Cox's Bazar.

Kutubdia is rich in producing salt and dried fish, locally known as 'Shutki'.

It has 58,463 households and a total area of 215.79 square kilometres (83.3 sq mi).

Climate change and sea level rise threaten to submerge the island in the Bay of Bengal.