巴纳纳尔岛（葡萄牙语：Ilha do Bananal，英语：Bananal Island），又名香蕉园岛，位于巴西托坎廷斯州，为世界上面积最大的河中岛，面积约20,000平方公里。该岛位于阿拉瓜亚河（Araguaia）中，长约350km，宽约55km。1959年，该地设为阿拉瓜亚国家公园。

Bananal Island (Portuguese:Ilha do Bananal, IPA: [banaˈnaw]) is a large river island formed from the bisection of the Araguaia River, in southwestern Tocantins, Brazil. The island is formed by a fork in a very flat section of the Araguaia River. Bananal Island is the second largest fluvial island in the world and the largest without an ocean coastline, at 350 kilometres (220 mi) long and 55 kilometres (34 mi) wide. Its total area is 19,162.25 square kilometres (7,398.59 sq mi).