Eric I, the Elder (German: Erich I., der Ältere; 16 February 1470 – 30 July 1540) was Duke of Brunswick-Lüneburg from 1495 and the first reigning prince of Calenberg-Göttingen.

Even in his early years Eric had proved himself as a brave fighter at the side of the emperors and took part in 1497 in the campaign against the Turks.

Eric I was the second son of Duke William II of Brunswick-Wolfenbüttel (d 1503) and received in 1491, before his father died, his inheritance of the Principality of Calenberg-Göttingen.

When the first marriage of the duke to the widow of Archduke Sigismund of Austria, Katharina of Saxony, proved childless, he married after her death on 7 July 1525 the 15-year-old Elisabeth of Brandenburg.

When, in 1528, Elisabeth fell ill in bed when she was pregnant, she held the witchcraft of her husband's mistress, Anna Rumschottel, responsible.

Between 1527 and 1530, he had the castle of Erichsburg built in a marshy depression about 3 km further east which was protected by a wide moat and high ramparts.

In 1523 abbey parish of St. Andrew in Derneburg placed itself under the protection of Eric I of Calenberg, because it had been repeatedly plundered by the knights of Duke Henry II of Brunswick-Lüneburg.

He left behind large debts, estimated at 900,000 thalers, as well as two important buildings: the Erichsburg near Dassel and the rebuilt Calenberg Castle.