Guaimar II (also Waimar, Gaimar, or Guaimario, sometimes called Gybbosus, meaning "Hunchback") (died 4 June 946) is the Lombard prince of Salerno from 901, when his father retires (or is retired) to a monastery, to his death.

His father is Guaimar I and his mother is Itta.

He is associated with his father in the principality from 893.

He is responsible for the rise of the principality: he restores the princely palace, builds the palace church of San Pietro a campanile, and restores gold coinage.