Assessing performance of mental health services (MHS) providers merely by their outcomes is insufficient. Process factors, such as treatment cost or duration, should also be considered in a meaningful and thorough analysis of quality of care. The present study aims to examine various performance indicators based on treatment outcome and two process factors: duration and cost of treatment. Data of patients with depression or anxiety from eight Dutch MHS providers were used. Treatment outcome was operationalized as case mix corrected pre-to-posttreatment change scores and as reliable change (improved) and clinical significant change (recovered). Duration and cost were corrected for case mix differences as well. Three performance indicators were calculated and compared: outcome as such, duration per outcome, and cost per outcome. The results showed that performance indicators, which also take process variability into account, reveal larger differences between MHS providers than mere outcome. We recommend to use the three performance indicators in a complementary way. Average pre-to-posttreatment change allows for a simple and straightforward ranking of MHS providers. Duration per outcome informs patients on how MHS providers compare in how quickly symptomatic relief is achieved. Cost per outcome informs MHS providers on how they compare regarding the efficiency of their care. The substantial variation among MHS providers in outcome, treatment duration and cost calls for further exploration of its causes, dissemination of best practices, and continuous quality improvement.