An important and crucial factor in the aspects of learning and teaching activities is motivation. In an online learning environment, students are sometimes faced with complex tasks that can reduce learning motivation. In computer learning environment, pedagogical agents were created to promote students’ motivation and learning outcomes. In this article the application of motivation theory in the construction of pedagogical agent motivation is explored. First, the theory of motivation is explained so that it may provide a clear picture of contemporary motivation theories that sometimes may appear similar. Second, motivation theories applied in online pedagogical agents are analyzed and reviewed. At the end of the article, several directions of design research for pedagogical agent motivation for the future are illustrated.