Illnau-Effretikon is a municipality in the district of Pfäffikon in the canton of Zürich in Switzerland. It includes the villages of Illnau, Effretikon, Ottikon and Bisikon. On 1 January 2016 Kyburg and Illnau-Effretikon merged to form the municipality of Illnau-Effretikon.

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.