This book constitutes the refereed proceedings of the 14th International Conference on Logic Programming and Nonmonotonic Reasoning, LPNMR 2017, held in Espoo, Finland, in July 2017. The 16 full papers and 11 short papers presented in this volume were carefully reviewed and selected from 47 submissions.

Invited Talks.- The Design of the Seventh Answer Set Programming Competition.- A Bird’s-Eye View of Forgetting in Answer-Set Programming.- Answer Set Programming and its Applications in Planning and Multi-Agent Systems.- From logic programming and non-monotonic reasoning to computational argumentation and beyond. - Nonmonotonic Reasoning Modular Construction of Minimal Models.- A Hasse Diagram for Weighted Sceptical Semantics with a Unique-status Grounded Semantics.- Foundations For A Probabilistic Event Calculus.- Contextual Reasoning: Usually Birds can Abductively Fly.- Including Quantification in Defeasible Reasoning for the Description Logic EL bot.- A Monotonic View on Reflexive Autoepistemic Reasoning.- The Minimal Inference Problem over Finite Domains: The Landscape of Complexity.- Answer Set Programming.- Gelfond-Zhang aggregates as propositional formulas.- Answer Set Solving with Bounded Treewidth Revisited.- Vicious Circle Principle and Formation of Sets in ASP Based Languages.- Answer Set Programs with Queries over Subprograms.- Explaining Inconsistency in Answer Set Programs and Extensions.- Blending Lazy-Grounding and CDNL Search for Answer-Set Solving.- Answer Set Programming with Graded Modality.- LPNMR Systems.- The ASP System DLV2.- lp2normal - A Normalization Tool for Extended Logic Programs.- Harvey: A System for Random Testing in ASP.- NoHR: Integrating XSB Prolog with the OWL 2 Profiles and Beyond.- ArgueApply: A Mobile App for Argumentation.- LPNMR Applications.- catnap: Generating Test Suites of Constrained Combinatorial Testing with Answer Set Programming.- Automatic Synthesis of Optimal-Size Concentrators by Answer Set Programming.- plasp 3: Towards effective ASP Planning.- Nurse Scheduling via Answer Set Programming.- Hybrid Metabolic Network Completion.- Action Language Hybrid AL.- moviola: Interpreting Dynamic Logic Programs via Multi-shot Answer Set Programming.- Adjudication of Coreference Annotations via Answer Set Optimization.