This chapter explores the determinants of private tutoring participation not only for education policy-makers and university planners but also for parents and students. It aims to an ongoing policy discussion on the expansion and prevalence of shadow education and its implications for high-stakes testing and National College Entrance Examination (NCCE) preparation. As long as the Hong Kong Diploma of Secondary Education Examination (HKDSE) and the Gaokao serve as the principal gatekeeper to Chinese higher education institutions, parents and students will continue to be motivated to pay for shadow education activities in the years ahead. The chapter argues that private supplementary tutoring (PST) plays a positive role in raising students' learning outcomes outside of the mainstream education system. However, this review also suggests that the inability to access high-quality private tutors can place lower-class students at a far greater disadvantage on NCCE scores compared to affluent urban students in China. Furthermore, high-income families can often afford greater quantities of PST.