Zone to Defend or ZAD (French: zone à défendre) is a French neologism used to refer to a militant occupation that is intended to physically blockade a development project. By occupying the land, activists aim to prevent the project from going ahead. The acronym "ZAD" is a détournement of "deferred development area" (from French: zone d'aménagement différé). The ZADs are organized particularly in rural areas with an ecological or agricultural dimension, although the name has also been used by occupations in urban areas, for example in Décines-Charpieu and Rouen.
The most notable example is the ZAD de Notre-Dame-des-Landes which helped a broader campaign to defeat the Aéroport du Grand Ouest, a proposed airport in Notre-Dame-des-Landes, north of Nantes. The ZAD du Testet existed from 2011 until 2015 and prevented a dam from being constructed. Evicted ZADs have amongst other things contested the construction of an electricity substation, a motorway and a facility for the storage of nuclear waste. There have been ZADs in the departments of Aveyron, Bas-Rhin, Doubs, Isère, Loire-Atlantique, Meuse, Seine-Maritime, Tarn and Yvelines. The occupation of the Hambach Forest in Germany and the No TAV movement in Italy have both been compared to ZADs. The ZAD de la Colline was the first Swiss Zone to Defend.