A meta-analysis of 68 studies examined the effectiveness of skills training for individuals with severe mental illness and the influence of such factors as methodological rigor, choice of outcome measures, and service settings. The methodological quality of these studies was generally very good. Skills training was found to be moderately to strongly effective in increasing skill acquisition and reducing psychiatric symptoms. However, effect size varied by type of outcome measure, with situationally specific measures yielding larger effects than measures of skill usage and role functioning. Studies rarely examined whether acquired skills were used outside the training setting. Surprisingly, most studies were confined to inpatient settings, and most focused exclusively on social skills. Implications are discussed for future research.