Teknaf (Bengali: টেকনাফ Ṭeknaf) is an upazila of Cox's Bazar District in the Division of Chittagong, Bangladesh.

The tidal range at the Teknaf coastal area is strongly influenced by the Naf river estuary.

The area has a warm tropical climate and sufficient rainfall to enable it to support wide biological diversity.

Teknaf Peninsula is one of the longest sandy beach ecosystems (80 km) in the world.

It represents a transitional ground for the fauna of the Indo-Himalayan and Indo-Malayan ecological sub-regions.