The Missouri Parents as Teachers (PAT) Parent Education Program is a voluntary and universal home visiting program available to all Missouri families who are expecting a child or who have a child ages birth to kindergarten entry. Families participating in the Missouri PAT Parent Education Program receive a variety of family support services, including family personal visits with trained parent educators to develop parent practices and child school readiness. Research indicates that home visiting components of parent education programs support child academic outcomes. However, studies have not extensively examined how variation in participation, including the developmental period of exposure—the child's age upon entry and duration of participation—and number and frequency of home/family visits, is associated with child outcomes. In this study, we used linear probability regression to examine associations between variation in participation in the Missouri PAT Parent Education Program and child third grade proficiency in math and English language arts (ELA) (n = 9777), while controlling for relevant child, parent, family, and school-level factors. We also tested the potential moderating role of family low-income status at enrollment into the program. We found that the number of family personal visits was positively associated with third-grade math and ELA proficiency, whereas no significant findings emerged for developmental period of program exposure. Our findings indicate that increased exposure to the Missouri PAT Parent Education Program was positively associated with third-grade academic achievement for all children, including those from low-income families.