Prince Alexander Philipp Maximilian zu Wied-Neuwied (23 September 1782 – 3 February 1867) was a German explorer, ethnologist and naturalist.

He led a pioneering expedition to southeast Brazil between 1815 and 1817, from which the album Reise nach Brasilien, which first revealed to Europe real images of Brazilian Indians, was the ultimate result.

His delicate health forced him to abandon his expedition, and he was detained on unfounded suspicions for four days, and robbed of a large part of his collection of insects and plants.

In 1832 he travelled to the Great Plains region of the United States, accompanied by the Swiss painter Karl Bodmer on a journey up the Missouri River, and wrote Reise in das Innere Nord-Amerikas (1840) on his return.

During his travels, he was a sympathetic recorder of the cultures of many of the Native American tribes he encountered, notably the Mandan and the Hidatsa, who lived in settled villages on the banks of the Missouri, but also such nomadic peoples as the Sioux, Assiniboine, Plains Cree, Gros Ventres and Blackfoot.