Improving ninth grade course passing rates has been shown to be crucial in improving high school outcomes. Yet at this critical transition to high school, family engagement has tended to decrease. This study explores how increasing use of the parent portal could potentially help to reduce ninth grade failure. Using automatically generated longitudinal portal access data from one large urban district, this study investigates the relationship between family use of the parent portal and the odds of students' course failure during ninth grade. Hierarchical linear model analyses showed a significant negative relationship between parent portal use and semester course failure, controlling for prior failing report card grades during the year and demographic variables associated with course failure. Although causal conclusions cannot be drawn from this study, the evidence supports and extends previous experimental studies of portal use. This suggests that efforts to expand parent portal use may potentially contribute to reducing students' course failure through increased monitoring and intervention efforts prior to the end of the semester. [For the Grantee Submission, see ED610835.]