Tangalle Fort (Sinhala: තංගල්ල බලකොටුව, romanized: Tangalla Balakotuwa; Tamil: தங்காலைக் கோட்டை, romanized: Taṅkālaik Kōṭṭai) is a small Dutch fort located in the coastal town of Tangalle, Sri Lanka.

The Dutch used Tangalle as an important anchorage on the southern coast of the island.

The four main walls, which are 12 m (39 ft) high, enclose a space similar to a rhombus, in height, in opposite corners of the structure.

The fort was significantly altered by the British in the middle of the 19th century when it was converted into a prison.

The British also used Tangalle as an anchorage.