Full Papers -- Policy-based Automated Compliance Checking -- Correctness of automatically generated choreography specifications -- Conflict-free Access Rules for Sharing Smart Patient Health Records -- Structuring Rule Sets Using Binary Decision Diagrams -- Link Traversal with Distributed Subweb Specifications -- Event-Based Microcontroller Programming in Datalog -- Combining deep learning and ASP-based models for the semantic segmentation of medical images -- A Two-Phase ASP Encoding for solving Rehabilitation Scheduling -- An Answer Set Programming based framework for High-Utility Pattern Mining extended with Facets and Advanced Utility Functions -- Automatic Generation of Intelligent Chatbots from DMN Decision Models -- Deep Learning For The Identification of Decision Modelling Components From Text -- Combining Sub-Symbolic and Symbolic Methods for Explainability -- Practical Rule-Based Qualitative Temporal Reasoning for the Semantic Web -- Logic Rules Meet Deep Learning: A NovelApproach for Ship Type Classification -- An Evaluation of Meta-reasoning over OWL 2 QL -- cl-psoatransrun: An Efficiently Executable Specification of PSOA RuleML in Common Lisp -- Leveraging the Power of IDP with the Flexibility of DMN: a Multifunctional API -- Technical Communication Papers -- Eliminating Harmful Joins in Warded Datalog+/- -- Learning decision rules or learning decision models ?

This book constitutes the proceedings of the International Joint Conference on Rules and Reasoning, RuleML+RR 2021, held in Leuven, Belgium, during September, 2021. This is the 5th conference of a new series, joining the efforts of two existing conference series, namely "RuleML" (International Web Rule Symposium) and "RR" (Web Reasoning and Rule Systems). The 17 full research papers presented together with 2 short technical communications papers and 2 abstracts of invited papers were carefully reviewed and selected from 39 submissions.