Building on social-cognitive theory and the expectancy-value theory, this study indicated that early parent expectations for children’s post-secondary educational attainment have a stronger effect on 8th-grade achievement than home-based parental involvement. With a nationally representative sample of kindergarten students and their parents in the United States of America, Structural Equation Modeling was employed in order to discern longitudinal effects on achievement via mediators. For instance, expectations held by parents in kindergarten exert much of their positive effect on adolescent academic achievement via expectations held in 8th grade. Student expectations (which are influenced by parental expectations) also significantly predict 8th grade achievement. Parent involvement in homework and grade checking in 8th grade has a slight negative effect on achievement. Home literacy in kindergarten predicts achievement in 8th grade indirectly via kindergarten achievement. These results indicate that parents can have a positive impact on academic achievement through early home literacy and maintaining a strong hope that their children will succeed in college. Because early parent expectations have long lasting effects on children, parent involvement interventions for young children need to be developed that also target elevating parental expectations. This study further clarifies the effects of the family environment on educational outcomes.