Although there is evidence to suggest that parent involvement (PI) in children's education positively impacts their academic success, the mechanisms of this effect are less well studied. One potential mechanism is a set of student-level motivational and behavioral factors labeled approaches to learning (ATL). The purpose of the current study was to utilize rigorous longitudinal methodology to evaluate whether ATL mediate the relationship between PI and student academic achievement. Using a large sample drawn from the Early Childhood Longitudinal Study--Kindergarten Cohort (ECLS-K), three sets of analyses were conducted focusing on three different types of PI (home-based involvement, school-based involvement, and home-school communication). Longitudinal mediation analyses indicated that only school-based involvement and home-school communication predicted student reading achievement and that this relationship was only mediated by ATL for school-based involvement. These findings contribute to the literature base on PI and represent a methodological advance to addressing these important mediational questions. Impact and Implications: The current study utilized rigorous methodology to examine whether approaches to learning, a variable including student motivation, persistence, and engagement, might help explain how parent involvement affects student achievement. Results indicated that approaches to learning explained this relationship partially for one type of parent involvement (school-based involvement). Additionally, the findings shed light on inconsistencies in prior research and the study demonstrated the use of appropriate methodology for answering these important questions.