House Rosby is an ancient noble house of The Crownlands. They rule the castle of Rosby and its surrounding village. The head of the house is Lord Gyles Rosby. They emblazon their arms with three red chevronels on ermine.
During the War of Conquest House Rosby bent the knee peacefully to Aegon I Targaryen, after Rhaenys Targaryen and her dragon Meraxes visited the castle. They were amongst the first to yield peacefully and not oppose the dragon. As a reward the current Lord Rosby was named Warden of the Sands during the First Dornish War, but was killed in the Defenestration of Sunspear.