Haguenau is a commune in the Bas-Rhin department of France, of which it is a sub-prefecture.

It is second in size in the Bas-Rhin only to Strasbourg, some 30 km (19 mi) to the south. To the north of the town, the Forest of Hagenau (French: Forêt de Haguenau) is the largest undivided forest in France.

Haguenau is a rapidly growing town, its population having increased from 22,644 inhabitants in 1968 to 34,891 inhabitants in 2006. Haguenau's metropolitan area has grown even faster in that period, going from 43,904 inhabitants in 1968 to 64,562 inhabitants in 2006.