House Mullendore is a noble house sworn to House Hightower of the Reach. They are located near Oldtown.

During the War of the Five Kings, House Mullendore supported Renly Baratheon. Mark Mullendore was a favorite member of King Renly's army due to the fact that he owned a black and white monkey.

At the Battle of the Blackwater, Mark Mullendore lost his arm and his monkey, and was captured. He was sent to the dungeons on Cersei Lannister's command when she was plotting against Margaery Tyrell.