In this study, the effect of technology supported problem-based learning activities on adults' self-efficacy perception for research-inquiry was investigated. Furthermore, determining the advantages and limitations of using Facebook in adult education were also investigated. In the study in which a total of 25 adults continuing their graduate studies participated, a qualitative and quantitative mixed method was employed. Problem-based learning activities during the course of curriculum development were supported by Facebook, one of the social networks. Designed with a single group pre-test and post-test design, the study has reached the conclusion that the adults are pleased with the activities. The results from the research revealed that problem-based learning activities supported by Facebook did not significantly affect adults' self-efficacy perceptions for research-inquiry avoidance and personal development, but that they provided a positive increase in perceptions of self-efficacy for sustaining research. The use of Facebook in adult education facilitates communication, information and resource sharing, access to resources, immediate feedback and correction, and effective use of time for learners. Moreover, Facebook provides an advantage for learners to cooperate with their peers and to participate actively in the learning process. However, besides its advantages, there are certain limitations of using Facebook in the educational environment. Learner's distance to using technology, problems experienced with internet access or distractions from the Facebook news feed can be stated as the limitations of Facebook.