The purpose of this study was to investigate the contributions of the actual and ideal L2 selves to L2 achievement/proficiency through achievement goals, using structural equation modeling (SEM) among 396 high school students learning English in Korea. Findings indicated that the actual L2 self significantly contributed to the English section of the Scholastic Ability Test (ESAT) directly and indirectly through the mediation of achievement goals as a whole. Even though the ideal L2 self did not contribute to the ESAT directly, it significantly contributed to the ESAT mediated by achievement goals as a whole indirectly, indicating that goals can drive motivation. In addition, the mediating effects of mastery approach goals (MAPG) were greater than those of performance approach goals (PAPG) in the paths from the actual and ideal L2 selves to the ESAT. These findings imply that students’ actual and ideal L2 selves can be enhanced more effectively, should achievement goals be incorporated.