Supervision has been identified as perhaps the most important mechanism for developing competencies in therapists in training. However, there is scant research on the effect of supervisors on client outcome. Moreover, in a relatively recent review of the existing literature, significant methodological concerns were raised that attenuate the interpretability of the existing reported findings. The current study therefore sought to address such methodological concerns. Crosstabulation of supervisors by client outcome categories (i.e., recovered, reliably improved, no reliable change, deteriorated) indicated that supervisors are significantly related to client outcome, generating a moderate effect. Training programs are therefore encouraged to routinely track client outcomes as an objective indicator of quality supervision. Additional implications for training programs and suggestions for future research are discussed.