The meteoric rise in the popularity of social networking sites (SNSs) has connected many employees with their contacts from work. However, clashes are catalyzed when individuals’ professional identities collide with their social ones. This paper aims to explore hotel employees’ identity conflicts stemming from cross-boundary friendships. Building on cognitive dissonance theory and conservation of resources theory, a multilevel model is proposed to examine how befriending colleagues on SNSs induces unfavorable workplace consequences through the mediation effect of identity conflict. The model further scrutinizes whether task interdependence intensifies this negative spillover. This study probes a novel identity issue aroused by SNS interactions in a professional context and advances research on interpersonal dynamics in organizations. It also provides new insights on the role of team-level situational factors. The results generate managerial implications for hotels and employees, suggesting that both groups should be better prepared for possible dilemmas embedded in cross-boundary relationships.