This book constitutes the refereed post-conference proceedings of the 19th International Conference on Computer Science and Education in Computer Science, CSECS 2023, held in June 2023 in Boston, MA, USA. The 23 full papers and 9 short papers were carefully reviewed and selected from 88 submissions. The papers cover many systems technologies, applications, and services as well as solutions. Multiple topics have been addressed including the theory of computation, models of computation, computational complexity and cryptography, logic, design, and analysis of algorithms, network architectures, performance evaluation, network services, software engineering, software creation, and management, applied computing, machine learning, and education.