Keith Percy married Joy Isabel Harrison in Hull on 18 August 1965. They have two children;
Helen Margaret Percy born 23 August 1966, Sutton, Surrey
Richard Philip Percy born 5 July 1968, Sutton, Surrey.
Richard Philip Percy married Rosemary Tromans on 29 July 1989 at Wellington, Shropshire. They have three children: Isabelle Helena Percy (born 1992), Robert Michael Percy (born1993) and Kathryn Eleanor Percy (born 2000).