Health workforce capacity-building is a key component of the updated National HIV/AIDS Strategy—provider-level interventions such as Project ECHO can help disseminate and standardize best clinical practices through virtual communities of practice and learning. Project ECHO in particular aims to reach providers with limited specialist access, and outcomes have historically focused on qualitative measures, i.e., provider confidence, self-efficacy, and professional satisfaction. This study explored patient viral load (VL) outcomes for medical providers participating in the University of Washington/Mountain West AETC’s Project ECHO program using 2011-2018 population-based data from Washington and Oregon (states which have comprehensive VL reporting systems). Patient demographic characteristics by Project ECHO participation status were generally similar. The percentage of patients with VL suppression (defined as VL ≤ 200 copies/mL) increased over time in both Project ECHO and non-Project ECHO cohorts, however, after adjusting for time, geographic location, and several patient and provider factors, participation was associated with an increased proportion of patients with VL suppression compared to no participation. Among patients of Project ECHO participants, overall VL suppression rate was significantly higher (by 13.7 percentage points) although authors note differences varied by provider PWH panel size. Additionally, greater improvement in the proportion of patients achieving VL suppression was observed among providers attending a larger number of ECHO sessions, though this also varied by panel volume.