Employment specialist competencies were examined as predictors of employment outcomes for consumers with serious mental illness participating in supported employment. Self-report and supervisor-rated performance measures from 57 employment specialists were correlated with three consumer employment outcomes (i.e., competitive employment rate, 90-day employment rate, and dropout rate). Employment specialists varied from 0 to 80% in the competitive employment rates for their caseloads. Supervisor ratings of job performance and employment specialist efficacy, percentage of time in the community, and frequency of contacts with consumers were associated with employment outcomes. Employment specialist self-report measures were unrelated to employment outcomes. Surprisingly, employment specialists with larger caseload sizes had higher employment rates. Employment specialists vary widely in their effectiveness. Behavioral measures and supervisory ratings of employment specialists were most predictive of employment outcomes. Direct observation of employment specialist job performance appears to be the most promising method for identifying competencies predictive of employment outcome.