拉加·拉格纳尔，Ragnheiður Ragnarsdóttir, also known as Ragga Ragnars is an Icelandic actress and former swimmer, who specialised in sprint freestyle events. She is a multiple-time Icelandic record holder in both long and short course freestyle. After retiring from swimming, Ragnheiður studied acting and has played the role of Gunnhild on the TV series Vikings since 2018.