The lattice Boltzmann method (LBM) is a mesoscopic approach to simulate fluid flow. Suitable for parallel computations, the LBM has efficiently simulated single-phase and multiphase fluid flow phenomena. The scheme is particularly successful in applications involving diffuse-interfacial dynamics. To date, much of the literature on the LBM's utility is limited to simple Cartesian grids. In this talk, I will present a novel numerical scheme which solves the lattice Boltzmann equations in complex geometries. A high-order spectral element discretization is employed on body-conforming hexahedral elements with Gauss–Lobatto–Legendre quadrature nodes. Using a discontinuous Galerkin framework, we impose the popular “bounce-back” boundary condition without the use of an extrapolation procedure. As a result, this approach provides accurate thermal-hydraulic measurement; namely, the Nusselt number on curvilinear boundaries. Computational results for benchmark test cases will be presented for applications in natural convection, conjugate heat transfer, and two-phase flows.