The objective of this study was to explore outcomes of preventive programs and psychosocial treatments for suicidal ideation and behaviour in gender sub-groups in mixed gender studies and in studies limited to one gender. The method used was a systematic review of randomized controlled trials (RCTs) which included women or men only, or reported and/or examined outcomes of psychosocial interventions in mixed gender samples. A total of 27 (18%) of RCTs reported or examined differences in intervention outcomes. Of the mixed gender RCTs, 5 (33%) reported greater effectiveness for females than males. The review identified promising interventions in female-only samples. None of the trials reported greater effectiveness of the intervention in men. The majority of reviewed studies looking at treatment outcomes in gender sub-groups showed no differences between women and men or indicated that some psychosocial interventions are effective for women. There is a need for studies which look at gender effects and development of interventions more effective and appealing for men at risk of suicide.