The purpose of this study was to investigate the effects of parental involvement on grades and achievement test scores through the variables time on task, general self-esteem, and student attitude about school. The study controlled for the background characteristics of ethnicity, gender, family background, and ability. To do this, structural models were developed based on theory, logic, prior research, and time precedence and were analyzed using 18,141 subjects from the High School and Beyond data set. Although parental involvement in the home had no direct effect on grades or achievement test scores in high school, it did affect time on task, general self-esteem, and attitude about school in such a way as to indirectly improve grades, especially through student attitude about school. When individual components of parental involvement were analyzed, consistent indirect effects on high school grades were found from fathers and mothers. The study suggests that if parents monitor school work, help with school plans, and talk to their child about personal experiences, their child's time on task, general self-esteem, and attitude about school will improve in a way that improves grades in school at the high school level.Ph. D.