The design and optimization of aerosol inhalers for pharmaceutical applications require a precise understanding of fluid dynamics to ensure effective drug delivery to the respiratory tract. A potent tool for modeling and examining the intricate relationships between airflow, particle behavior, and device shape in aerosol inhalers is computational fluid dynamics, or CFD. The concepts of CFD are examined in this chapter along with how they are used to create effective and patient-centered inhalation devices. The function of CFD in maximizing aerosol production, particle deposition, and dispersion within the respiratory system is one of the main subjects. There includes discussion of case examples showing how CFD may be used to enhance device performance, cut down on medication waste, and guarantee repeatability. Additionally, the chapter addresses developments in boundary conditions, turbulence models specifically designed for inhalers, and numerical modeling. Critical analysis is done on issues such integrating CFD findings with real-world clinical circumstances, validating CFD results with experimental data, and the requirement for computational efficiency. This chapter highlights the revolutionary role that computational fluid dynamics (CFD) plays in developing the next generation of aerosol inhalers for respiratory therapy by bridging the gap between theoretical fluid mechanics and real-world device engineering.