Solidarity behaviour (SB) among employees is important in building a sense of community in organizations, particularly within a crisis context where adverse working conditions prevail. However, we have limited knowledge concerning how SB develops. Using the lens of social exchange theory, this study examines how top-down communication and employee voice relate to horizontal (employee to emplCoyee) SB. We conducted two comprehensive studies during the Greek economic crisis and found that the relationship between top-down employee communication and horizontal SB is mediated by employee voice. The paper extends our existing knowledge in the fields of management and human resource management by advancing our understanding of horizontal SB, highlighting the role of top-down employee communication as an effective human resource practice and delineating the role of employee voice in fostering workplace camaraderie in small and medium-sized enterprises under crisis.