The purpose of this study is to investigate paths of the effects of L2 motivational self system and self-efficacy on Korean EFL learners’ English ability. For this purpose, questionnaires were conducted and 580 Korean elementary school students in Gyeonggido participated in this survey. Correlation and path analysis were used to analyze the data. The major results of the study are as follows: (1) Self-efficacy is correlated with all constructs of motivation. It has the highest correlation with ideal L2 self and the lowest correlation with ought-to L2 self; (2) self-efficacy has a direct effect on ideal L2 self and ought-to L2 self whereas it has direct and indirect effects on elementary students’ English proficiency; and (3) ought-to L2 self has a positive direct effect and L2 learning experience has a negative direct effect on elementary students’ English proficiency. However, ideal L2 self has no effect on elementary students’ English proficiency. At the end of the paper, pedagogical implications and suggestions are discussed.