Alv Erlingsson (Alv Erlingsson den yngre, died 1290) was a Norwegian nobleman, earl of Sarpsborg and governor of Borgarsyssel. Alv Erlingsson was born at Tanberg in Norderhov, Buskerud. Alv Erlingsson was the son of Erling Alvsson of Tanberg (ca. 1230–1283) and grandson of Alv Erlingsson of Tanberg (ca. 1190 – ca. 1240). Tanberg (Tornberg) was an old manor which was considered to have been among the oldest farms in Norderhov. His grandmother was Ingeborg Baardsdatter of Rein, sister of Duke Skule Bårdsson. Alv Erlingsson was also a second cousin of King Magnus VI of Norway.