Tu Ky (Vietnamese: Tứ Kỳ) is a district (huyện) of Hải Dương province in the Red River Delta region of Vietnam.

As of 2003 the district had a population of 167,664.

The district covers an area of 168 km2 (65 sq mi).

The district capital lies at Tứ Kỳ.

This article about a location in Vietnam is a stub.