On October 28-31, 2019, Guglielmo Marconi University, in collaboration with Metadata and Semantics Research Conference, held the 13th International Conference on Metadata and Semantics Research (MTSR’19) in Rome. MTSR is an annual international inter-disciplinary conference that brings together academics, researchers and practitioners in the fields of metadata, ontologies and semantics research. The conference was an unparalleled opportunity for participants to share knowledge and novel approaches in the implementation of semantic technologies across diverse types of information environments and applications. These include Open Access Repositories and Digital Libraries, Cultural Informatics, Digital Humanities, E-learning applications, Search Engine Optimization and Information Retrieval, Research Information Systems and Infrastructures, e-Science and e-Social Science applications, Agriculture, Food and Environment, Bio-Health & Medical Information Systems. The conference took place thanks to the keen collaboration between the General Chair members, Emmanouel Garoufallou, International Hellenic University, Greece and Ernesto William De Luca, Georg Eckert-Institute – Leibniz-Institute for International Textbook Research, Germany. Thanks to the incredible Program Chair, Noemi Scarpato, San Raffaele Roma Open University, Italy, and thanks to the local Organization Chair, Francesca Fallucchi, Guglielmo Marconi University, Italy.