Facebook is currently the most popular social networking site, and it has been used in a number of collaborative learning applications. In a collaborative learning environment, an adaptive learning companion could help learners understand the learning content and share knowledge, as well as increase creativity and facilitate the beneficial effects of collaborative learning. In this study, a learning companion recommendation system (LCRS) is developed on Facebook, which supports mobile collaborative learning. The system collects friends' profile data automatically according to their learning needs, such as interests and professional abilities. Moreover, the technology acceptance model and partial least squares regression are used to investigate learners' acceptance of the LCRS for learning activities