Aim:This study aimed to analyse the mediator effect of role ambiguity betweensocial support from supervisor and colleagues and job satisfaction in Portuguesenursing staff.Background:Few studies have analysed the processes through which social supportincreases job satisfaction in the nursing context.Design:A cross-sectional design using questionnaires.Method:A total of 124 registered nurses and 130 certified nursing assistants par-ticipated in the study. Mediation analysis was performed by calculating percentileconfidence intervals (10,000 resamples).Results:Mediation analysis revealed a partial mediation between social support andjob satisfaction through role ambiguity. The direct effect was greater in the case ofsupervisor support.Conclusions:Social support is a crucial resource in the nursing work context with abeneficial effect on well-being (e.g. reducing role stress) and job satisfaction.Implications for Nursing Management:Managers of hospitals and health units canestablish the organizational bases to facilitate this process, considering the impor-tance of the role of the supervisors and colleagues in the provision of high levels ofinstrumental and socio-emotional support.