This review explores several aspects of trichotillomania relevant to clinical theory and practice. It is concluded that research outlining the phenomenology and patterns of comorbidity of trichotillomania have been advanced significantly in recent years. However, no current diagnostic category appropriately classifies trichotillomania. Research with nonclinical populations suggests that trichotillomania is more common than previously believed and that additional epidemiological research is warranted. Continued elaboration of existing etiological models incorporating varying theoretical perspectives is also encouraged. Assessment of trichotillomania could also be improved by the continued development of reliable and valid standardized measures. This article reviews both pharmacological and psychological treatments for trichotillomania, with an emphasis on habit-reversal training. Though some interventions appear effective in the short-term, reported relapse rates are high and future research on treatment for trichotillomania should focus on improving long-term outcomes. It is clear that despite a recent flux of research centering on trichotillomania, significant challenges for understanding and treating this psychological disorder still exist for researchers and clinicians. Based on this review of the literature, and on our clinical experience with trichotillomania, we propose directions for future research with this underserved psychiatric group.