In a global knowledge society, self-directed learning ability is a core competency to prepare students for the future because they need to constantly acquire the necessary knowledge in a given situation. Primary school is the time for students to start learning English, and developing the ability to learn English on their own at this time can have a great impact on the continuity and success of English learning in the future. This study aims to investigate the following: 1) what is the level of self-directed learning ability of Korean elementary English learners? 2) which factors among the sub-factors of self-directed learning positively or negatively influence English learners’ self-directed learning ability? 3) how are self-efficacy and students preference for collaborative learning related to self-directed learning ability? For this purpose, 548 fifth and sixth grade elementary school students were surveyed. The results of the study were as follows. First, the English learners’ self-directed learning ability turned out to be ‘below average’. The 5th graders had significantly higher scores than the 6th graders. The female students were higher than the male students, and the students with private education were much higher than those without private education. Second, the learners had high responsibility and ability to use learning strategies, while they had low English learning motivation and ability to control their behavior. Third, self-directed learning ability was found to be highly correlated with self-efficacy and students preference for collaborative learning. These results suggest that to improve English learners’ self-directed learning ability, it is necessary to provide students with opportunities to successfully perform their tasks in cooperation with colleagues, along with strategic training to develop self-directed learning skills.