This book gathers the contributions presented at the 15^th International Benchmark Workshop on Numerical Analysis of Dams held in Milan in September 2019. These Benchmark Workshops are promoted by the Technical Committee – Computational Aspects of Analysis and Design of Dams of ICOLD (International Commission of Large Dams) to provide an opportunity for engineers, researchers and operators to present and exchange their experiences and the latest developments in dam design, performance and monitoring. This series of almost semi-annual events was launched in Italy in 1991 and has since been hosted in several countries around the world. The themes and approaches considered in the different editions reflect the evolution of analysis tools and safety evaluation criteria in recent decades. The first benchmarks were focused on the validation of numerical codes, often developed by companies internally. The predictive capabilities of codes also available commercially are the committee’s latest challenges. The aspects of greatest interest concern the selection of the most appropriate geometric and constitutive models and the calibration of the parameters with the aim of making the numerical modeling increasingly realistic. The 15^th International Benchmark Workshop on Numerical Analysis of Dams addressed three main topics: Topic A considers the seismic response of a concrete gravity dam; Topic B refers to the seismic analysis of a loose material dam; Topic C introduces the pre-breaking and breaking behavior of a levee.