This study investigated the relationships among intrinsic and extrinsic motivation, learning strategies, and second/foreign language (L2) achievement. A self-report questionnaire of the Motivated Strategies for Learning Questionnaire (MSLQ) was administered to 291 university students learning English in Korea to collect data about motivation and learning strategies, and L2 achievement was determined by the grade of an English reading course. The results of data analysis using the Pearson product moment correlation and structural equation modeling (SEM) were as follows: first, the correlations among intrinsic motivation, extrinsic motivation, self-efficacy, learning strategies, and achievement were all significant, with intrinsic motivation and self-efficacy the highest and intrinsic motivation and extrinsic motivation the lowest correlations. Second, the model (Model 4) explaining the contributions of extrinsic motivation and self-efficacy to achievement mediated by learning strate-gies fit the current data better than other competing models (Models 1, 2, and 3). Third, significant direct effects of extrinsic motivation and learning strategies on achievement were found, whereas a significant indirect effect of self-efficacy on achievement by way of learning strategies was detected. The implications of these findings were discussed in terms of the contributions of extrinsic motivation, self-efficacy, and learning strategy use to L2 achievement, followed by future study areas to shed further light on relations among motivational components, learning strategies, and L2 achievement.