Atmospheric dispersion and chemical transport models (CTMs) are a key tool in both atmospheric chemistry and environmental sciences. From urban air pollution modeling to ozone depletion, these models give us a picture, at different scales, of the distribution of species concentrations and pollutant deposition rates, among other relevant quantities. These models help us to interpret observational data which, in some cases, are sparse and incomplete. The papers included in this Special Issue, "Atmospheric Dispersion and Chemistry Models: Advances and Applications", published between 2022 and 2023, cover several developments and applications related to atmospheric dispersion and chemistry models. These studies highlight the potential benefits of using such models for many scientific and technical applications in atmospheric chemistry and environmental sciences, involving, for example, the characterization of aerosols and chemical species in the atmosphere, and risk analyses and decision making for potential pollutant releases, nuclear accidents, and climate change.