Rendsburg-Eckernförde (German pronunciation: [ˈʁɛnt͡sˌbʊʁk ɛkɐnˈføːɐ̯də] ⓘ; Danish: Rendsborg-Egernførde) is a district in Schleswig-Holstein, Germany.

It is bounded by (from the east and clockwise) the city of Kiel, the district of Plön, the city of Neumünster, the districts of Segeberg, Steinburg, Dithmarschen and Schleswig-Flensburg, and the Baltic Sea.

In 1867 the Prussian administration established twenty districts in its province of Schleswig-Holstein, among them the districts of Rendsburg and Eckernförde.

The district is situated at the coast of the Baltic Sea, roughly between the cities of Schleswig and Kiel.

A large portion of the Kiel Canal passes through Rendsburg-Eckernförde.