William Ellerbe Pelham Jr. is an American clinical psychologist known for his research on ADHD. He is Distinguished University Professor and director of the Center for Children and Families at Florida International University. He was educated at Dartmouth College and the State University of New York at Stony Brook. He is a fellow of the American Psychological Association (APA) and the American Psychological Society, and he has served as president of the APA's Division 53 (the Society of Clinical Child and Adolescent Psychology) and the International Society for Research in Child and Adolescent Psychopathology.