This study investigated the relationship between parental involvement in children's education and the academic achievement of primary six pupils in Edo State, Nigeria. The ex-post facto research design was employed in this study. The sample consisted of 1,895 primary six pupils (1,024 males and 863 females drawn from 37,908 primary six pupils in Edo State, Nigeria. An instrument labeled (PIRS) was used to collect data from the sample. Data analysis indicated that parental involvement significantly influenced pupils' academic achievements in three core subjects, English Language, Mathematics and Integrated Science, in primary school and that the higher the parental involvement, the higher the achievement of pupils in the three core subjects. Based on these findings, it was recommended that parents be more involved in the education of their children/wards and that parents monitor their children's school attendance. In addition, school counsellors and educational psychologists should employ diverse approaches to achieve greater parental involvement in their schools.