This paper investigates the effect of aero-acoustic parameters on the efficiency of acoustically-driven drug delivery (ADD) to human maxillary sinus (MS). To be more specific, the effect of the frequency, amplitude at the acoustic excitation, and the inlet mean flow rate on the efficiency of ADD to the MS is studied. Direct computational aero-acoustics, using a validated computational fluid dynamics (CFD) model, has been utilised to carry out the parametric study. The transport pattern of the particles (drugs) in the presence of an external acoustic field has been investigated through the discrete phase model. Extensive computational simulations have revealed that the most important parameter in acoustically-driven drug delivery to the MS is the amplitude of the oscillation of the air plug in the ostium, which is largest when the combination of nasal cavity and MS is at resonance. Also, it has been found that the amplitude of the inlet acoustic wave has a direct correlation with the efficiency of the drug delivery to the MS. Moreover, the inlet mean airflow rate adversely affects the efficiency of the drug delivery to the MS. The results of this study suggest that applying an external acoustic field after distributing the drug particles with no mean flow results in a better drug delivery than in the presence of an inlet mean flow.Copyright © 2020 Elsevier B.V. All rights reserved.