The Zeno brothers, Nicolò (c. 1326 – c. 1402) and Antonio (died c. 1403), were Italian noblemen from the Republic of Venice who lived during the 14th century. They came to prominence in 1558, when their descendant, Nicolò Zeno the Younger, published a map and a series of letters purporting to describe an exploration made by the brothers of the north Atlantic and Arctic waters in the 1390s. The younger Nicolò claimed the documents were discovered in a storeroom of his family home.

Widely accepted at the time of publication, the map was incorporated into the works of leading cartographers, including Gerardus Mercator. Modern historians and geographers have disputed the veracity of the map and the described voyages, with some accusing the younger Zeno of forgery.

Nicolò and Antonio were brothers of the Venetian naval hero Carlo Zeno. The Zeno family was an established part of the aristocracy of Venice and held the franchise for transportation between Venice and the Holy Land during the Crusades. According to the younger Zeno, the map and letters date from around the year 1400 and describe a long voyage made by the Zeno brothers in the 1390s under the direction of a prince named Zichmni. Supporters of a legend involving the contemporaneous Scottish nobleman Henry Sinclair, Earl of Orkney suggest that Zichmni is a mistranscription of d’Orkney. The voyage supposedly traversed the North Atlantic and, according to some interpretations, reached North America nearly a century before the voyages of Christopher Columbus.