This study examined differences in South Korean students' motivation to learn English as a foreign (EFL) from elementary to high school, and investigated the impact of private education experience on their English learning. A questionnaire was administrated to 7,957 students in elementary through high school. This cross-sectional survey results revealed that EFL students' motivation to learn English presented different levels of medians depending on their school grades and levels; it showed lowering trends from the elementary to high school levels. However, during the same period, students' perceptions of the importance of learning English was not in a downward trend. Students with private education experience tended to have a higher level of motivation than did those without private education experience, especially with respect to instrumental, intrinsic, and integrative motivations. Socio-educational factors in South Korea, such as excessive pressure from the College Scholastic Ability Test and hakbul orientation, are discussed.