This book constitutes the refereed proceedings of the 14th Latin American Symposium on Theoretical Informatics, LATIN 2020, held in Sao Paulo, Brazil, in January 2021. The 50 full papers presented in this book were carefully reviewed and selected from 136 submissions. The papers are grouped into these topics: approximation algorithms; parameterized algorithms; algorithms and data structures; computational geometry; complexity theory; quantum computing; neural networks and biologically inspired computing; randomization; combinatorics; analytic and enumerative combinatorics; graph theory. Due to the Corona pandemic the event was postponed from May 2020 to January 2021.