Gronau is a town and a municipality in the district of Hildesheim, in Lower Saxony, Germany. It is situated on the river Leine, approx. 15 km southwest of Hildesheim, and 35 km south of Hanover. Since 1 November 2016, the former municipalities Banteln, Betheln, Brüggen, Despetal and Rheden are part of the municipality Gronau.
Gronau is also the seat of the Samtgemeinde ("collective municipality") Leinebergland.
Honiton (UK) is twinned with Gronau.
- Armin Kaufmann (1922-1985), born in Banteln, lawyer and university lecturer
- Jürgen Mlynek (born 1951), physicist
- Media related to Gronau at Wikimedia Commons