Lucy is the youngest of Jane, Fred, and Jessica's sisters, and Dave's youngest daughter. She appears in the episode "D.W. Thinks Big", where she is married, and D.W. saves her wedding ring. She is an aardvark with blonde hair. In the episodes "Go to Your Room, D.W.", "D.W.'s Perfect Wish", "D.W. Unties the Knot", and "Grandpa Dave's Memory Album", Arthur and D.W. mistakenly refer to Lucy as their cousin instead of their aunt.