Gildehauser Venn, Nature reserve in Bad Bentheim, Germany.

Gildehauser Venn is a 650-hectare nature reserve in northwest Lower Saxony featuring birch forests, peat pools, and sand ridges. The landscape includes open moorland with scattered water bodies and dune formations typical of this wetland ecosystem.

Parts of the Venn were first protected as a nature reserve in May 1938. The reserve reached its current size of 650 hectares in 1985, with a 350-hectare core zone where all use is banned. A 1995 management plan guides its care, and large fires in April 1996 and March 2014 each damaged up to 150 hectares before the vegetation recovered.

The name derives from Low German 'Fenn', meaning moor, used for the cross-border moorland between Gildehaus and Gronau. The reserve is part of the EU Natura 2000 network as the 611.4-hectare FFH area Gildehauser Venn. Visitors can look for breeding waders such as curlew, lapwing and snipe; black-tailed godwit and redshank no longer nest here.

The reserve is accessible via Vennweg in Bad Bentheim with clearly marked walking paths of varying distances. Local tourism information provides guided tours and advice on the best times for bird watching.

The reserve hosts several carnivorous plant species including bladderwort and sundew, which trap insects using sticky tentacles along the paths. These rare plants thrive in the nutrient-poor, acidic peat waters.