Empirical research on parental involvement in children's education often makes the assumption that levels of involvement remain fixed over time. This paper highlights evidence from a longitudinal study that half of parents of young people in Year 9 reported becoming more or less involved in their child's school life over a two-year period and explores the characteristics associated with mothers and fathers that change their levels of involvement. The young person's attitude to school, the mother's relationship with the school, attendance at parents' evenings and the mother's ethnicity, qualifications and change in economic status had the strongest associations with a reported change in maternal involvement levels. Changes in paternal involvement were strongly associated with the father's ethnicity and the young person's behaviour. (Contains 3 tables and 2 notes.)