Westerdeichstrich is a municipality belonging to the Amt ("collective municipality") Büsum-Wesselburen in the district Dithmarschen in Schleswig-Holstein on the West Coast of Germany.

It consists of the parts Westerdeichstrich, Groven, Augustenhof and Stinteck.

Westerdeichstrich is located at the North Sea coast north of Büsum and west of the old dam which connected Büsum with the mainland in 1585.

The most notable building in Westerdeichstrich is its windmill "Margaretha" from 1845, now serving as a restaurant.

The mill is also featured in the coat of arms, alongside a spade in reference to dike building and a mermaid in reference to the importance of tourism for the town.