大厦谷战争（西班牙语：Guerra del Chaco），又译为格兰查科战争、查科战争，1932年－1935年玻利维亚和巴拉圭两国为争夺格兰查科北部而进行的战争。

格兰查科（Gran Chaco）位于巴拉圭河以西、安第斯山脉以东、亚马孙盆地以南，潘帕斯草原以北，面积约65万平方公里，但人烟稀少、缺乏物产。玻利维亚和巴拉圭对格兰查科北部约26万平方公里土地的归属一直存在争执。20世纪20年代，在该地发现了石油后，两国为争夺石油资源纷争愈加激烈，从1928年起，两国之间频频发生武装冲突。而世界主要石油巨头以及邻近国家也卷入其中，美孚石油公司和智利支持玻利维亚，英荷壳牌石油公司和阿根廷支持巴拉圭。

The Chaco War (1932–1935) (Spanish:Guerra del Chaco, Guarani: Cháko Ñorairõ) was fought between Bolivia and Paraguay over control of the northern part of the Gran Chaco region (known in Spanish as Chaco Boreal) of South America, which was thought to be rich in oil. It is also referred to as La Guerra de la Sed (Spanish for "The War of the Thirst") in literary circles, for being fought in the semi-arid Chaco. It was the bloodiest military conflict fought in South America during the 20th century, between two of its poorest countries, both having previously lost territory to neighbors in 19th century wars.