The present study is aimed at examining the links between L2 self-guides and self-determination theory (SDT). 429 Korean university students participated in the study and their responses to the questionnaires on L2 self-guides in the 2 x 2 model and autonomous motivation of SDT were analyzed. The results show that, first, promotion focused L2 self-guides were found to share some characteristics with autonomous motivation, that is, intrinsic motivation and identified motivation. Second, these two types of motivation appeared to have stronger predictor values for motivated learning behavior than L2 self-guides with a promotion focus. Lastly, these L2 self-guides' relationship with motivated behavior was found to be completely mediated by autonomous motivation. This indicates that when considering the relationship between students' L2 self-guides and their motivated effort, autonomous motivation should be taken into account.