This minisymposium focuses on modern high-order techniques for the numerical simulations of geophysical and environmental flows. High-order methods have shown great potential for improving the numerical simulation of the compressible or incompressible Euler and Navier–Stokes equations, Boussinesq-type equations, and the shallow water equations, across various geophysical regimes. The minisymposium will cover high-order spatial discretization techniques in the horizontal and vertical directions (e.g., discontinuous Galerkin, semi-Lagrangian, high-order finite volume, spectral element methods, multilayer-moment models) as well as high-order, efficient and stable time integration strategies for multiscale geophysical problems and novel structure-preserving discretizations (e.g., well-balanced, equilibria-preserving, positivity-preserving, energy-conserving, entropy-stable, and asymptotic-preserving schemes). The minisymposium will address the many challenges associated with the application of high-order methods to environmental flows. In particular, while high-order methods implemented on the same mesh as low-order methods remain computationally expensive and therefore require scalable parallel solvers and modular implementations, their use on coarser meshes introduces different challenges, such as representing unresolved flow scales or sub-grid topography/bathymetry scales. Applications include, but are not limited to, coastal, oceanic, and atmospheric flows, as well as coupled problems involving moist advection, cloud resolution, sediment and plastic transport. The goal of this minisymposium is to create a venue where methods developed independently for different environmental applications can be compared and cross-fertilized, encouraging speakers to highlight not only their results but also the modeling assumptions and discretization choices behind them, so as to stimulate discussion on which techniques generalize across the different flow regimes represented.