Massive Open Online Courses (MOOCs) are widespread and still growing due to their modernity and proliferation. However, one of the concerns of MOOCs is the high dropout rate of enrollees. Focusing on this issue, especially in Saudi Arabia where there is a lack of literature and special characteristics such as adopting single-sex education system, was an essential reason for conducting the current study. This study examined the relationship among learners' motivation, gender, and completion of MOOCs in Saudi Arabia. Keller's ARCS motivation model was used as the theoretical framework. In this non-experimental survey study, 238 Saudi learners of MOOCs completed the Instructional Materials Motivation Survey (IMMS). Chi-square tests, independent samples t-tests, multiple regression, and logistic regression were used to analyze the data. The findings showed a low dropout rate and a significant relationship between gender and motivation in MOOCs. Also, females indicated higher motivation levels than males. In addition, there was a positive relationship between learners' motivation and completion of MOOCs. The results can be beneficial for online learning stakeholders as well as MOOCs providers, designers, and researchers in Saudi Arabia. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]