Eyvind Lambi or Eyvind Lamb was a Norwegian Viking and hersir of the late ninth and early tenth centuries, known from, among other sources, Egils saga. Eyvind was the son of the Viking Berle-Kari and brother-in-law of Kveldulf Bjalfason, who married Eyvind's sister Salbjorg Karadottir; he was thus uncle to Skalla-Grímr and Thorolf Kveldulfsson and great uncle to the famous poet Egill Skallagrímsson. Eyvind also had a brother named Olvir Hnufa, who became a famous skald at the court of King Harald I of Norway.
Like his brother Olvir, Eyvind joined his nephew Thorolf Kveldulfsson on a number of Viking expeditions after the latter received a longship as a gift from his father Kveldulf. They gained a great deal of profit from such voyages. At a thing in Gaular, Olvir fell in love with Solveig Atladottir, the daughter of a jarl in Fjordane named Atli the Slender. The jarl refused Olvir permission to marry the girl, but he was so smitten that he abandoned his Viking life to be near her. Eyvind continued to voyage with Thorolf for some time thereafter.
Together with Thorolf, Eyvind made his way to the court of King Harald of Vestfold, who was in the process of conquering the Norwegian kingdoms and uniting Norway under his rule. His brother Olvir had already joined the court as a skald. However, after swearing allegiance to King Harald, Eyvind returned home with his father Kari. With Olvir and Thorolf, Eyvind fought at the Battle of Hafrsfjord (c. 872/885) aboard Harald's flagship. Eyvind is thereafter not mentioned until the death of Thorolf at the hands of King Harald (c. 900), at which time he administered to those wounded in the battle. Eyvind assisted Thorolf's widow Sigrid in administering her estates. He subsequently married Sigrid on King Harald's orders. Egil's Saga relates that Eyvind and Harald "remained friends for the rest of their lives."