The purpose of this study was to investigate how learner variables (motivation, learning style types, attitude toward writing, and computer literacy) and support of teachers influenced learners’interaction (participation, interaction content, and interaction form) in a web-based case discussion in which pre-service early childhood teachers participated. Participants were 131 students majoring in early childhood education who were taking a course that combined an offline and online discussion at a Women’s College. Learners’participation was analyzed in terms of the total numbers of messages that they wrote online and the total numbers of messages and other instructional materials that they read. Interaction content was analyzed in terms of social, cognitive, and meta-cognitive dimension. Interaction form was analyzed in terms of initiative and responsive dimensions. Learners responded to a questionnaire that investigated learners’ motivation, learning style, attitude toward writing, computer literacy, and teacher support. The overall findings of this study were as follows: Learners motivation (external goal orientation, value on tasks, self-efficacy, control beliefs for learning), learners’learning styles, and support of their teacher influenced learners’ participation, interaction content, and interaction form in the web-based discussion. However, learners’ attitude toward writing and computer literacy did not affect their participation, interaction content, and interaction form in the web-based discussion.