Research in a variety of contexts suggests that parental involvement is correlated with children’s educational success; however, studies are lacking that evaluate the relationships between English private tutoring (EPT), parental involvement, and students’ academic performance. To address this gap, this paper investigates the effects of parental involvement on the academic attainment of Taiwanese students with a focus on the breadth of EPT. Data from the Taiwanese national college entrance exams in 2017 and 2018 were collected to obtain and design a pretest–posttest control group. Based on the results of a two-stage least squares regression analysis, the findings revealed that parents’ private tutoring (PT)-related activities, parent–school contacts, EPT, and self-learning were significantly associated with students’ increased academic gains in comparison to certain dimensions of parental involvement, such as discussions between the parents and their child/children and the monitoring of the child/children by the parents.