Burnout among community mental health (CMH) therapists has been associated with poorer therapist health, higher agency turnover, poorer client outcomes, and compromised quality of care. Recent mandates to learn and implement multiple evidence-based practices (EBPs) within CMH settings are intended to improve the quality of community care, yet there is mixed evidence concerning the impacts on workforce burnout. The current study sought to identify correlates of therapist emotional exhaustion, a key aspect of burnout, during the sustainment phase of a system-driven implementation of multiple EBPs in children’s mental health services. We hypothesized that high workload and unfavorable organizational climate would relate to therapist emotional exhaustion, but that positive experiences with EBPs adopted would relate to lower exhaustion. Although agency-level indices of organizational climate were unrelated to exhaustion, a multilevel model revealed that therapists’ weekly work hours, caseload, and number of EBPs delivered were associated with increased emotional exhaustion. Additionally, activities associated with the EBP implementation efforts (e.g., hours spent in EBP-related activities, supervision or consultation, or outcome monitoring), were not associated with emotional exhaustion. Therapists’ knowledge and confidence delivering EBPs and their positive perceptions of EBPs were protective against emotional exhaustion, but these perceptions did not buffer the risks associated with heavy workload. Findings point to implementation strategies to prevent burnout and associated turnover that compromise the returns on investments in EBP implementation.