Ragnvald "the Wise" Eysteinsson (830–890) (Old Norse: Rögnvaldr Mærajarl), was jarl of Sunnmøre, Nordmøre, and Romsdal. He died at the Orkney Islands.

He was son of King Eystein "Glumra (the Noisy)" Ivarsson of Oppland. His maternal grandfather was King Ragnvald the Mountain-High of Vestfold. One of his paternal great-grandfathers was King Halfdan the Old of Oppland.

His second wife was Ragnhild Hrolfsdottir (Raghldr (Hldr) Hrolfsdóttir), daughter of Hrolf Nefia (Hrolfr Nefjaa). Ragnvald was the father of Hrolf Ganger, the founder of Normandy, and Turf-Einar, ancestor of the jarls of Orkney.

He is a direct ancestor of William I of England, Edward III of England, James I of England, and Elizabeth II of the United Kingdom of Great Britain and Northern Ireland. He is therefore an ancestor of most of the royal families of Europe.

He is rumored to have been the one to cut the hair of king Harald Hårfagre (Fairhair) after he became king over all of Norway.