Valgard Arngrimsson (825-868) was a Norse Viking and brigand during the late 9th century. In 868, a man from Tref Manaw on the Isle of Man hired him and several other bandits to assassinate Bjorn Tall-Trunks on his return to Dyflin from Ynys Mon, but Bjorn killed all of them and found the patron's letter instructing them to meet him at Tref Manaw.