This book constitutes the thoroughly refereed proceedings of the 5th Joint International Semantic Technology Conference, JIST 2015, held in Yichang, China, in November 2015.The theme of the JIST 2015 conference was "Big Data and Social Media". The JIST 2015 conference consisted of main technical tracks including 2 keynotes, 2 invited talks, a regular technical paper track (full and short papers), an in-use track, a poster and demo session, workshop, and tutorial. The 14 full and 8 short papers in this volume were carefully reviewed and selected from 43 submissions. The paper cover the following topics: ontology and reasoning, linked data, learning and discovery, RDF and query, knowledge graph, knowledge integration, query and recommendation, and applications of semantic technologies.