Dietikon is the fifth biggest city of the canton of Zürich in Switzerland, after Zürich, Winterthur, Uster and Dübendorf. It is the capital of the same-named district of Dietikon and part of the Zürich metropolitan area.

The canton of Zürich is a Swiss canton in the northeastern part of the country. With a population of 1,553,423, it is the most populous canton in the country. Zürich is the de facto capital of the canton, but is not specifically mentioned in the constitution. The official language is German. The local Swiss German dialect, called Züritüütsch, is commonly spoken.