Spawned by the heightened competition in mainstream education, supplementary tutoring outside regular school time has rapidly expanded as a common practice of students seeking to gain a competitive edge in school. It is widely known that students from low socioeconomic status (SES) families lag behind their high-SES peers in academic performance. This study examines whether extra lessons reinforce or weaken the family effect on educational inequality. We use the Programme for International Student Assessment 2009 data to analyze the effect of family SES on the likelihood and intensity of students’ extra lesson attendance in four Chinese regions: Shanghai, Taiwan (Chinese Taipei), Hong Kong, and Macao. The research confirms that (1) high-SES students are more likely than low-SES students to receive extra lessons, and (2) among the students who participated, high-SES students also invested more time each week in such lessons. However, the study has also found substantial regional differences.