Previous research shows inconsistent relationships between parent involvement and academic achievement and often asks why such inconsistencies occur. The research proposes a theoretical model that separates parent involvement into those practices linking parents to children and those practices linking parents to other adults in the school environment. The researcher hypothesizes that parent-child (i.e. discussion and monitoring) and parent-school (i.e. educational support strategies and Parent Teacher Organization involvement) practices will differentially affect student attitudes (educational expectations), behaviors (absenteeism, homework, truancy), and achievement (math and science). Using a national survey conducted in the United States of schools and students, the National Education Longitudinal Study (NELS:88), The research estimates a series of hierarchical models to test the direct and indirect effects of parent involvement on student attitudinal, behavioral and academic outcomes. Findings confirm that parent-child and parent-school involvement practices differentially influence student attitudes and behaviors, thereby indirectly affecting student achievement -- to varying degrees.