This book constitutes the refereed post proceedings of the 18th International Conference on Parallel Computational Technologies, PCT 2024, held in Chelyabinsk, Russia, in April 2024. The 22 full papers included in this book were carefully reviewed and selected from 62 submissions. These papers have been organized under the following topical sections: High Performance Architectures, Tools and Technologies; Parallel Numerical Algorithms and Supercomputer Simulation.