This book constitutes the proceedings of the 20thInternational Conference on Logic for Programming, Artificial Intelligence, andReasoning, LPAR-20, held in November 2015, in Suva, Fiji.
The 43 regular papers presented together with 1 invitedtalk included in this volume were carefully reviewed and selected from 92submissions. The series of International Conferences on Logic for Programming,Artificial Intelligence and Reasoning, LPAR, is a forum where, year after year,some of the most renowned researchers in the areas of logic, automatedreasoning, computational logic, programming languages and their applicationscome to present cutting-edge results, to discuss advances in these fields, andto exchange ideas in a scientifically emerging part of the world.