Brains (French pronunciation: [bʁɛ̃] ⓘ; Gallo: Brâin or Brein, Breton: Brenn) is a commune in the Loire-Atlantique department in the Pays de la Loire region in western France.

Neighbouring communes are Le Pellerin, Cheix-en-Retz, Port-Saint-Père, Saint-Léger-des-Vignes, Bouaye, Bouguenais, La Montagne and Saint-Jean-de-Boiseau.

Jules Verne was welcomed there by his uncle Prudent Allotte de la Fuye, owner from 1828 to 1837, during his summer vacations.

The rectory was sold as national property during the Revolution, and is now "l'espace des Clos Mâts", a cultural site with a library and music.

Port Hamoneau, witness to the economic importance of the Acheneau until 1914 for the export of wine and red sand to Nantes, now welcomes hikers and anglers who come to enjoy the peace and quiet of the surrounding marshes, in the shade of the poplar trees.