The Linguistic Association of Korea Journal, 29(3), 41-66. The purpose of this study was to identify the structural relationships and the mediating effects among instructor-learner interaction, self-directed learning ability, and task value influencing learning flow in online college English courses. For this purpose, a web survey was administered to 252 university students who attended classes in the spring semester of 2020. The data was analyzed using structural equation modeling, and the mediating effect was verified by the Sobel test. The major findings are as follows. First, the structural relationship among the variables was established except for self-directed learning ability. Second, self-directed learning ability and task value had positive effects on the learning flow. Third, instructor-learner interaction had a significant effect on the learning flow by mediating learners' task value. In conclusion, in order to encourage university students to be engaged in the class, it is necessary to prepare teaching and learning methods to improve self-directed learning ability and the perception of task value based on interaction with learners.