Self-efficacy, motivation, and learning strategies are crucial in second/foreign language (L2) acquisition and general learning. However, we are not sure yet the unique or combined contributions of self-efficacy to learning strategies by way of instrumental and integrative motivation. The purpose of this study was to investigate the role of self-efficacy in learning strategies mediated by instrumental and integrative motivation by developing two hypothetical models and testing these models using structural equation modeling among university students learning English in Korea. Findings indicated that self-efficacy directly as well as indirectly contributed to learning strategies through the mediation of a composite variable of motivation as a whole. However, when instrumental and integrative motivation were mediated separately from each other, only the indirect, not direct, contribution of self-efficacy to learning strategies reached a significant level. In addition, even though the participants were more instrumentally than integratively motivated, it was integrative, not instrumental, motivation that significantly contributed to learning strategies. These findings imply that the effect of strategy instruction could be improved if self-efficacy and motivation are incorporated into instructional approaches.