Mobile social media are increasingly being used in education. They provide an effective way to address the imbalance between teaching supply and demand for older adults. However, few studies have investigated which factors contribute to older adults’ intention to use mobile social media for learning. This study uses a sequential explanatory mixed method to investigate the factors impacting older Chinese adults’ adoption of mobile social media for learning. Results of the quantitative phase indicated that Technology Anxiety (TA), Self-efficacy (SE), Previous Experience (PE), and Subjective Norm (SN) had significant effects on Perceived Usefulness (PU). TA, SE, PE, and Facilitating Conditions (FC) had significant effects on Perceived Ease of Use (PEU). PU and PEU are significant predictors of Behavioral Intention (BI), and PEU had a positive effect on PU. In the qualitative study, the significant effects of these extension factors on PU and/or PEU were investigated further. Perceptions and concerns about using mobile social media for learning were analyzed based on the participants’ interview data. On the basis of these results, recommendations are made to promote the use of mobile social media for learning by older adults. Specifically, teachers and colleges should: (a) select appropriate social media applications and set up relevant courses, and (b) supply inexpensive network service and high-quality learning support service. These research results have important implications for academic researchers, senior college managers, and teachers.