Previous studies in the neuroscience and psychology literature works suggest that poor sleep quality is associated with emotion dysregulation, and that poor sleep quality and emotion dysregulation are, independently, associated with the presence and severity of psychiatric symptoms. However, no previous study has examined simultaneous relations among multiple different emotion regulation strategies, sleep quality, and mental health outcomes. Such investigations are particularly important given the extensive literature describing the prevalence and manifestation of poor mental health outcomes in university students. This study investigated the influence of both maladaptive (avoidance and impulsivity) and adaptive (cognitive reappraisal) emotion regulation strategies on sleep quality and, subsequently, on the degree of depressive and posttraumatic symptomatology in a sample of South African university students ( N = 336). Participants completed self-report instruments measuring their tendency to use avoidance, cognitive reappraisal, and impulsivity; their sleep quality; their accessibility to social support; and their number of depressive and posttraumatic symptoms. Structural equation modelling showed that more use of avoidance and impulsivity and less use of cognitive reappraisal negatively affected sleep quality, which, in turn, was associated with the presence of more depressive and more posttraumatic symptoms. Hence, our findings suggest that emotion regulation indirectly exerted its influence on the manifestation of psychiatric symptoms through sleep. We conclude that interventions targeted at improving sleep quality may prove beneficial in lessening the burden of depressive and posttraumatic symptoms in university students.