Demographic and psychological predictors of parent involvement with their children's science education both at home and at school were examined during high school. Associations between both types of parent involvement and numerous academic outcomes were tested. Data were collected from 244 high school students in 12 different science classrooms using surveys, the Experience Sampling Method (ESM), and school records. Results revealed low overall parent involvement. Demographic characteristics predicted parent involvement at school, but not at home, while student reported interest in science predicted both. Different dimensions of parent involvement affected outcomes differently. Among the most pronounced influences were those that parent involvement at home had with student efficacy, interest in science, and motivational states in science class. (Contains 3 tables.)