Social media has become an important part of learning due to the advancement of technology and the importance of asynchronous interaction. The ability to learn anywhere at any time is especially supported by Facebook groups, which provide a private means of interaction with others who share the same interests. In such groups, sharing information from around the world in a collaborative manner can result in erroneous beliefs in misinformation. This descriptive quantitative study examined the collaborative learning that takes place in private social media groups, and the role of critical thinking in group efficacy. Data collection relied on results from a combination of the Facebook Learning Scale, Self-Assessed Collaboration Scale, and sections of the Adult Decision-making Competence. Findings revealed high group efficacy and collaborative skills. Data analysis supported the use of Online Collaborative Learning Theory as a framework, and positive correlation between group effectiveness and collaborative ability. While there was no significant correlation between critical thinking and group efficacy, further analysis showed a significant ability of group members to think critically regarding the social norms of others. Lack of significant difference in reports of efficacy across age, gender and length of group membership shows that social media groups can be as effective as face-to-face collaboration. The results of this study bolster the use of social media groups for collaboration in both higher education and adult learning. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]