DescriptionResearch suggests that Facebooking can be both beneficial and detrimental for users’ psychological well-being (“Facebook Paradox”). However, the specific effects of Facebooking on individuals’ social relationship satisfaction and psychological well-being remain inconclusive. Using structural equation modeling, causal pathways were examined between Facebook intensity, online and offline social relationship satisfaction, perceived social support, social interaction anxiety, and psychological well-being. Personality differences on each of those casual paths were also assessed. Employing a sample of 342 university students, results indicated that intensive Facebooking positively predicted users’ psychological well-being through online social relationship satisfaction, and simultaneously negatively predicted users’ psychological well-being through offline social relationship satisfaction. Furthermore, perceived social support mediated the path from Facebooking to psychological well-being, and social interaction anxiety mediated the path from offline social relationship satisfaction to psychological well-being. Taken together, the present study suggests that when and how Facebooking is helpful or harmful to users’ psychological well-being depends on both user characteristics and online-offline social contexts.