This book constitutes the proceedings of the 15th Latin American Symposium on Theoretical Informatics, LATIN 2022, which took place in Guanajuato, Mexico, in November 2022. The 46 papers presented in this volume were carefully reviewed and selected from 114 submissions. They were organized in topical sections as follows: Algorithms and Data Structures; Approximation Algorithms; Cryptography; Social Choice Theory; Theoretical Machine Learning; Automata Theory and Formal Languages; Combinatorics and Graph Theory; Complexity Theory; Computational Geometry.