The volume is a collection of high-quality, peer-reviewed research papers presented at the Third International Conference on Mathematical Modeling and Computational Science (ICMMCS 2023), held during 24 - 25 February 2023 in hybrid mode. The topics covered in the book are mathematical logic and foundations, numerical analysis, neural networks, fuzzy set theory, coding theory, higher algebra, number theory, graph theory and combinatory, computation in complex networks, calculus, differential educations and integration, application of soft computing, knowledge engineering, machine learning, artificial intelligence, big data and data analytics, high performance computing, network and device security, Internet of Things (IoT).