This quasi-longitudinal study explored changes in motivation and attitudes of Korean high school English learners from 2002 to 2010.A total of 1,471 students completed the same questionnaire in 2002 (364 students), 2006 (673), and 2010 (434).Nine motivational factors were observed over the years: instrumental, extrinsic, intrinsic, cultural-exchange, heuristic, international posture, selfdevelopment, competitive, and amusement motivation.Among the factors, competitive motivation was increasingly influential in the students' EFL learning, and demonstrated a significant, positive correlation in 2006 and 2010.On the other hand, despite the globalization of English, the role of international posture became less dominant for Korean high school students.The overall explanatory power of motivational/attitudinal factors for proficiency gradually decreased over the years.Based on the findings, it is suggested that English teachers help EFL learners reflect on their personal meanings of learning English instead of excessively focusing on competition with peers.