Background: Limited data are available on the implementation of an area under the concentration-time curve (AUC)-based dosing protocol with multidisciplinary team (MT) support to improve adherence with vancomycin dosing protocol. Objective: To evaluate the effectiveness of an AUC-based dosing protocol with MT support intervention with adherence to a hospital-wide vancomycin dosing protocol at Thammasat University Hospital. Method: We conducted a quasi-experimental study in patients who were prescribed intravenous vancomycin. The study was divided into 2 periods; (1) the preintervention period when the vancomycin dosing protocol was already applied in routine practice and (2) the post-intervention period when the implementation of an AUC-based dosing protocol with MT support was added to the existing vancomycin dosing protocol. The primary outcome was the rate of adherence, and the secondary outcomes included acute kidney injury events, vancomycin-related adverse events, and 30-day mortality rate. Results: In total, 240 patients were enrolled. The most common infections were skin and soft-tissue infections (24.6%) and bacteremia (24.6%). The most common pathogens were coagulase-negative staphylococci (19.6%) and Enterococcus spp (15.4%). Adherence with the vancomycin dosing protocol was significantly higher in the postintervention period (90.8% vs 55%; P ≤.001). By multivariate analysis, an AUC-based dosing protocol with MT support was the sole predictor for adherence with the vancomycin dosing protocol (adjusted odds ratio, 10.31; 95% confidence interval, 4.54-23.45; P ≤.001). The 30-day mortality rate was significantly lower during the postintervention period (8.3% vs 20%; P =.015). Conclusions: AUC-based dosing protocol with MT support significantly improved adherence with vancomycin dosing protocol and was associated with a lower 30-day mortality rate.