There has been a growing interest among educators and researchers in studying Massive Open Online Courses (MOOCs) and their impact on education. Issues and problems have been reported in the research and in practice, including problems related to MOOC learners' motivation and engagement during the course. However, very few studies have adopted a design-based research (DBR) approach based on educational theories or instructional design models to solve these problems. These approaches would provide practical guidance to educators and designers, and would then contribute to refining the theories or models. The present study aimed to contribute to better understanding of MOOC leaners' motivation for the course and their engagement in the course as well as how MOOCs can be better designed to promote learners' motivation. The study implemented motivational strategies from the ARCS (Attention, Relevance, Confidence, and Satisfaction) motivational design model in a MOOC. The study also aimed to explore learners' motivation and their engagement and learners' perceptions of the motivational design strategies in the course. Furthermore, it intended to provide practical implications in increasing learners' motivation in MOOC design and enhancing the understanding of the ARCS model in MOOCs. The study first presented the motivational design results and then systematically integrated ARCS motivational design strategies into MOOC instructional design. Then MOOC learners' reactions, in terms of the four components of ARCS in regards to the whole course design, were explored preliminarily by the Instructional Materials Motivation Survey (IMMS), which was designed specifically for the ARCS model. Learners' perceptions of the ARCS motivational design strategies were examined in more depth through online/phone interviews. The researcher also kept a design journal documenting the design process and feedback about the course design. Based on implementation of the first iteration, modifications of the ARCS motivational design strategies were implemented and applied to the second iteration. The findings indicated that MOOC learners enrolled in courses for a variety of reasons. Potential fun and enjoyment from the courses was an important factor. The results revealed that many MOOC learners selectively paid attention to information that was closely related to their goals for the courses and ignored the other information. Relevance of MOOCs was self-decided to a large extent for many learners. Although many MOOC learners in this study were confident that they were able to achieve their goals, the instructor's encouragement and sympathy for the learners in videos were effective in increasing their confidence. Learners' satisfaction could come from different aspects. For example, some learners were proud because they were able to complete a course successfully; some felt achieved for the knowledge they gained from the course. Although obtaining the statement of accomplishment (SOA) was not the goal for all learners in the study, the SOA did contribute to the sense of satisfaction. Videos and instructors were critical components that they affected learners' experience in MOOCs greatly. A large number of learners participated in this study were self regulated and used many study strategies to help learning. Based on these results, implications for designing motivational strategies from the ARCS model were provided for MOOC environments. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]